In the dangerous expanses of open water, it can pay to be a small fish. So small, in fact, that you can hide in a snail shell. Meet evolution’s curiosities from Tanganyika.
WORDS: NATHAN HILL
Based upon chutzpah to bodyweight ratios, the shell dwellers of Lake Tanganyika will always get my vote as the bravest fish in the world. Whether their brazenness really is courage or just stupidity is hard to pinpoint, but they have a vicious streak wider than the lake they inhabit. Keep some at home, and I guarantee that they will bite you one day.
Being bitten by one of the ‘shellies’ is actually pretty cute, thanks to their pygmy statures. The normal impression of a fierce cichlid is some burly, biting submarine of a thing, like the heavyset curs of Central America — the kind of fanged apex predator that has little to fear to begin with.
Shell dwellers tear this impression apart. They are small fish, among the smallest cichlids in the world, and they carry overtones of prey, not predator. But their hearts are those of berserkers, and they will dash headlong into the face of an intrusive human diver, to land a menacing bite upon the tip of the nose. Make no mistake, they want you dead. If every fish in the world behaved like these, then we humans would never have set foot into water. Our boats would be torn out from underneath us, like an aquatic remake of Hitchcock’s ‘The Birds’.
In order to live up to the name of ‘shell dweller’ a fish needs to be pretty small, and their dinky size is advantageous when it comes to seeking out real estate. Curling up inside the curves of a snail shell is a great way to make yourself trickier to swallow.
Tanganyika is the hot spot for fish that live this way, though it’s not the only place it happens. In neighbouring Lake Malawi there’s another cichlid — Pseudotropheus lanisticola — that has also worked out the value of diving into these makeshift caves. Hermit crabs around the world are famous for commissioning shells of all kinds for themselves. But the shell dwellers of Tanganyika take living in old snail husks to an all-new level, making up large urban sprawls — shell cities — with their ad-hoc buildings.
There are different levels of shell dependency between species, and different social structures are built around them. A fish may be facultative, and only use a shell temporarily, if at all. Or they may be obligate, unable to fend for themselves in the lake if they are denied one.
The real surprise of shell dwelling is that it hasn’t evolved as a wider trait. Soft, small fish have long sought solace from larger mouths, and when caves are lacking it’s usually a case of improvise, swim away, camouflage or be digested.
There’s more to shells than just defence. Having all of your neighbours in easily recognisable homes makes it all the easier to keep tabs on who’s who — who has stayed and who has strayed. For the kind of male fish that likes to keep a harem, it’s the ultimate in family enforcement, allowing control and surveillance of a population.
Socially, shell dwellers may live in vast colonies, or they may live in small, pocketed outreaches. There may be a degree of respect for territorial boundaries, or they may behave like warrior tyrants, stealing females and shells from each other, and ravaging their enemy’s fry as they live in a permanent state of hostility.
In Tanganyika, the choice of shell is really only the one: Neothauma tanganyicense. At 6cm/2.4in, this is the largest gastropod in the lake, and the only species in the genus.
Calcium-heavy snail shells are liable to dissolve in fresh water, but because of the intense mineral concentrations within the lake, they last for decades. Neothauma are largish lumps, and successful with it, and their populations can be vast. It’s common to find areas of several square kilometres, with shells strewn like pebbles. In fact, it’s easier to underestimate how vast these shell congregations can be: in places there may be piles of 3m deep. Subsequently, it’s possible to find large areas populated by swathes of shell-dwelling cichlids.
For the aquarist, the appeals are huge. Shell dwellers are, by their very nature, small. That means they don’t require the huge tanks associated with other lake dwellers like mbuna. Because of their sociable natures, species pending, quite large numbers can be kept in relatively small tanks. They feed easily, and breed readily. They have fascinating behaviours worth studying. And if that’s not enough, you can even keep plants in a tank with them. Try that with other African cichlids and see what happens.
To get all of that from one fish, and at the tiny drawback of the occasional comedic nip, I’m surprised that ‘shellies’ are not the most popular African cichlid in the UK. They’re certainly easy enough to house.
Keeping shellies at home
Whichever species you keep, the considerations are basic. First and foremost is tank size, which needn’t be huge. For a single pair of the smallest fish (like Neolamprologus brevis) then a mere 45 x 30cm/18 x 12in footprint is needed. For the largest species, like the beastly, 12cm/4.8in long Lamprologus callipterus, then just 90cm/36in will suffice.
To do things properly, bigger will be better, and will allow you to consider a Tanganyika community with other carefully considered fish. If you want a real good stab at doing a social group of shellies, then consider a tank of 100cm/40in or more. I’ve seen set-ups for these fish of 150cm/60in long, and the fish behaved just like they were still in the lake.
Fine sand is an absolute must. In the wild, these fish dig like crazy. Often it’s the only way they can obtain fresh shells, in the hugely competitive housing market that is shell-dweller city. Avoid coarse coral sand, and plump for one of the finer sands like aquarium silver sand. Some of the ultra-fine, almost dusty substrates like those from JBL are worth a look. Not all of these fish are exclusively shell-inhabitants, and some prefer to dig pits or burrows nearby. A substrate depth in excess of 5–6cm/2–2.4in in some parts of the tank will help them facilitate this.
Decoration is a huge consideration. If you’re housing shellies with other Tanganyikans like Julidochromis, then you need to carefully divide the tank into distinct ‘rock’ and ‘shell’ zones. The problem is this — rock dwellers place an invisible barrier around their rocks, while shellies do the same with their own unique homes. If those territories overlap, the two disputing fish will fight until one backs down or dies.
Just breaking up lines of sight won’t work. If you try placing a visual windbreak between the designated areas, then a rock dweller will try to occupy it, and make a territory around it. It’s considerably safer to leave a clear gap of at least 15cm/6in between the two camps.
Getting the right shells is essential. Too small and the fish will outgrow them rapidly, and then squabble over the remaining few that fit. There will be casualties. Too big or heavy and you’ll deny the fish the ability to move the shells around, ruining a central part of their social dynamic.
It can be tempting to get a bag of assorted marine shells from a retailer and hope for the best, but many of these will be marine whelk types, and far too cumbersome for shellie use. The discarded shells of garden snails can be the right size, though care needs to be taken that they haven’t been contaminated with pesticides. Soaking and rinsing will usually render them safe.
Escargot shells — those from edible snails — are also a near enough size and shape, and can be obtained easily enough from online sources. A soak and a rinse for good measure are still recommended. Whichever shell you opt for, get more than you think you need. Aim for three or four shells for every fish, otherwise there’ll be squabbling.
Being from Tanganyika, the water requirements of all species are the same. You want water that’s harder than trying to read Nietzsche, with an exorbitantly high pH value.
Try to get the pH as close to 9.0 as you can without going over. That means you’ll
want some buffering salts, unless you happen to live with the most caustic water supplies in the UK. A hardness level up around 20°H is no problem here; indeed it may be prerequisite.
Some coral gravel and crushed oyster shell mixed into the substrate, or ocean rock as decor will help to keep pH up, while specially tailored mineral supplements can be used to buffer hardness. Some of them are accurate to a high degree, mimicking the composition of Tanganyika closely, and while not cheap, they do come recommended, especially if you’re considering buying up wild caught fish. Seachem, JBL, Continuum and a heap of other companies have their own products in this line.
Keeping the hardness high is as important as getting it there in the first place, so be wary of factors that can force it down. Trapped food and waste between the shells and in the substrate will have an acidic effect, so regular syphoning of the base is needed. This is when you’ll be bitten most, as the fish will see your hand as a carnivorous intruder, heading down to gobble their eggs and upset their loved ones.
CO2 can have a small but chronic effect, as in high concentrations it lowers pH. Effective gas exchange through surface movement will help here.
Remember that plants aren’t ruled out of a shell dweller tank. These fish are carnivores and uninterested in greenery, and so provided you stick with species able to tolerate the extreme water conditions, then go right ahead. Vallisneria, which struggles in soft tanks, tends to fare well (and some kinds are even found in the lake, making it biotope correct) while the near immortal Anubias, as always, will happily tie to any rocks in the tank.
Aim for filters with ample biological capacity (externals rank highly) as the alkaline conditions of the water mean that any ammonia present will be in its most toxic form. Flow needn’t be directed any which way in particular, but aim for good circulation through the tank. If there’s just enough ‘lift’ to carry particles out from between shells and into the filter, then you’ll save yourself a lot of work.
What to keep with them
Tank mates need some forward planning. Julidochromis, and cylindrical Neolamprologus types may seem the immediate sensible choice, but go sparingly. All of these fish live close to the base and can soon get under each other’s skin.
Higher water fish are worth a look, especially in larger tanks. Aulonocranus is a good choice, and will keep out of the shellies’ way. I’ve seen shellies mixed with Tropheus types before, too, though this requires a vigilant eye.
Stick to fish from the lake. The temptation is to add fish like bristlenose Ancistrus to help curb algae growth, but these are soft water dwellers that struggle with the chronic onslaught of minerals working through their little kidneys.
That’s about as difficult as it gets. If you can provide the above, then you’ve got the makings of a generic shellie tank.
Told you it was easy, didn’t I?
4 shell dwellers for your aquarium
The frog-faced, bulldog-chinned baby of the shell dwellers, N. brevis is one of the more peaceful species. Still, they’ve drawn blood from me on more than one occasion.
N. brevis are small, fierce, and the species you’ll most likely meet in stores. At a distance, their beige colours aren’t too endearing, but observe closely and you’ll spot blue undertones and warpaint splashes of colour over the cheeks. There are a few regional morphs with unique markings, such as ‘sambia’ and ‘katabe’.
As shellies go, they don’t live in vast congregations, and are the wiser choice if you struggle to source an abundance of shells.
Pronunciation: Nee-oh-lamp-row-low-gus brev-iss.
Size: To 6cm/ 2.4in in adult males.
Water: Hard, alkaline: 7.8–9.0pH, hardness 15-25°H.
Diet: Go easy on flakes. Offer lots of brine shrimp, Cyclops, Daphnia and Calanus. Frozen is fine.
Sexing: Difficult when young, males will eventually be larger than females.
Spawning: Add three females to every male, get the temperature up to 25–26°C/77–79°F and condition with hearty feeds of Cyclops. She’ll duck into a shell and lay eggs while he waits at the entrance. As she exits, he fertilises them without even entering. Then he’ll be shooed away and she’ll look after the young. Eggs hatch in around 24 hours, fry are free swimming after a week. Ensure lots of tiny food like infusoria.
Maybe the cutest of all, you definitely want deep sand for these fish. They love to bury their shells, making a kind of funnel around the mouths out of the substrate. This has a double effect of concealing the home, and also encouraging tiny organisms to fall in, like a miniature Sarlacc pit from Star Wars. This second feature is especially handy for raising young.
L. ocellatus are good in large colonies, so don’t be shy about stocking. A 120cm/48in tank with a dozen or more of these shellies is a tremendous sight. Smother the base of the tank with shells and leave them to it.
Pronunciation: Lamp-row-low-gus oss-ell-ah-tuss.
Size: To 5.8cm/2.3in.
Water: Hard, alkaline: 7.8–9.0pH, hardness 15–25°H.
Diet: Daphnia, Cyclops and flake food works well.
Sexing: Look at the fin edges. Males have a gold trim, while females have white. Males are also bigger.
Spawning: Just like N. brevis, except the young get a better start by virtue of the funnel shaped shell openings.
More than likely still sold under the older name of Lepidolamprologus hecqui, this is a shell dweller sitting in the middle of the size ranking. These are easily hefty enough to get your finger in their mouths, so while smaller shellies hit and run, these guys grab and swing.
They’ll form harems, with a male dominating, so if you’re keeping groups then keep eyes open for a straggler potentially being bullied. It happens. If you’re tight for space, they’ll behave just fine as a male and female pair. If they spawn, note that nothing — nothing — will be allowed near them, so if your sneaky Julidochromis are getting a hammering, then it’s safe to say there are young around.
Pronunciation: Nee-oh-lamp-row-low-gus heck-key.
Size: To 8cm/3.1in.
Water: Hard, alkaline: 7.8–9.0pH, hardness 15–25°H.
Diet: Daphnia, Calanus, flakes and pellets.
Sexing: Look at adult faces. Males have a bigger, bulldog jaw and a slight bump on the nose. They’re also physically bigger.
Spawning: A conditioned pair left to their own devices at 25°C/77°F will start going through the motions. Fry hatch in 24 hours, free swimming young appear after five days. Feed meaty foods like Walter worms from the free swimming stage.
The smallest cichlid species in the world? At just 4.5cm/1.8in fully grown, it’s a tiny contender for that humble distinction.
For the shellie fan with limited space, this is the fish to go for. A 45cm/18in tank will house a couple of pairs, or a decent harem for one male. They are easy to keep, easy to source, and cheap enough to buy. If you’re looking for a shell-dweller entry point, I’d definitely choose these!
Pronunciation: Nee-oh-lamp-row-low-gus mull-tee-fash-ee-ah-tuss.
Size: To just 4.5cm/1.8in.
Water: Hard, alkaline: 7.8–9.0pH, hardness 15-25°H.
Diet: Daphnia, Cyclops and flake foods work well.
Sexing: Look at the upper dorsal fin. If it has a red tinge about it, then you have a male. Aside that, wait for them to grow as males are much larger.
Spawning: Just like N. brevis.
Love them or hate them, the bright blue fish are here to stay, but it’s amazing how little is known of these manufactured species. We explore the big three of the electric blue guild – the Acara, the Ram and the Dempsey.
WORDS: NATHAN HILL
Manipulated fish in the hobby are being increasingly normalised. In some cases, with beasts like the curious and distinctly ‘un-fishy’ Parrot cichlids, they are conceivably more popular than normal cichlids.
Some fish blur the definitions of hybrids or genetic mutations. When we think hybrid, we often think of a collision of species, resulting in some kind of distinct chimera. We imagine the massive pronounced heads of Flowerhorn cichlids, or the novel mind-pickling that comes with seeing a Red tailed catfish with a shovelnose ‘beak’.
That’s not always the case. With modern man-made fish, traits tend to be augmented rather than crudely bolted on and obvious. Given how many times I’m asked the wild provenance of the Electric blue Acara, for example, it seems the breeders have achieved their aim of duping the hobby with an ‘authentic enough to be natural’ fish.
But then not all our aquarium oddities are forced amalgamations of species. The progenitor to the electric blue craze was probably the Electric blue Jack Dempsey, Rocio octofasciata, and what we know of that fish now suggests anything but mixed blood. Instead, the blue of this fish has all the hallmarks of being a mutation, nothing beyond a ‘faulty’ gene throwing up more colour than would be found in any wild fish.
In some cases, it seems blue is an inevitability. With a fish as genetically plasticine as the Ram cichlid, mutations are abundant — that’s why we see the likes of Balloon ram, Long-fin rams, Golden rams, Giant rams and, the stars of today’s retail show, the Electric blue rams. Here, selective breeding along with a chance mutation tossed up the fish we see today.
Regardless how you might feel about ‘fake’ fish like these, they have become an integral part of the hobby. and it’s worth taking time to investigate just what makes them tick…
Electric blue Dempsey
How the debate rages over these. Are they hybrids, aren’t they hybrids? The answer seems to be a contested ‘no’, they are not, based on DNA analyses of females. You’d normally expect a DNA test to put this kind of thing to bed, but the debate goes on that the hybrid gene may somehow linger in the males only. Still, the hybrid case is decidedly weak.
However, that’s not to say that the line breeding position is perched upon an ivory tower. Line breeding usually involves dollops of inbreeding, in an attempt to get the greatest yield from a desired trait. Look at fancy goldfish, for example. There’s no hybridisation involved in the making of a Bubble eye or a Ranchu, but those fish are very far removed from their ancestors.
The downside to the line breeding of the Jack Dempsey is that no two Electric blues ever appear the same. Bent spines are commonplace (and note the slow but obvious appearance of ‘balloon’ morphs creeping in) as is irregular muscle growth, and knife backed fish with a ‘wasting disease’ appearance are all too frequently spotted. Most prominent of all, the heads of the fish are now as individual as any human faces. There are flat faced, long faced, fat, thin, sloped, and squared heads out there, plus more. Jaws may look natural, squat or underslung like a bulldog’s, and everything in between.
The true wild Jack Dempsey is a brute. It was named after a famed boxer of the day, in homage to its predilection for fighting. Rocio octofasciata has drawn aquarist blood before, and will do again. They hail from Central America, namely Honduras, Mexico, Guatemala and Belize, where they live wherever the hell they feel like it. They are generalists in the truest sense, adopting rivers, ponds, lakes, canals, streams and drainage ditches as their homes. Reaching 20cm/8in fully grown, and being a solid chunk of muscle, little gives them cause for concern.
Which makes the limp nature of the Electric blue variants something of a disappointment, or a bonus, depending which way you look at it. Yes, the aggression is still sort of there, but it’s diluted down; more like a child with a temper than a traditional frenzied Celtic warrior.
The benefit of that is that Electric blues have more than a chance of being housed alongside fish their wild counterparts would demolish. Small fish are a bit of a no-no, and though you might imagine that other cichlids would be problematic, I’ve seen them housed in mixed mid-sized cichlid communities with the likes of Oscars, Convicts and the ever-present Parrot cichlids. I’ve even seen them ignoring big Angelfish and gouramis. These are strange times.
Scientific name: Rocio octofasciata.
Origin: Central America.
Habitat: Multiple, from streams to lakes.
Size: To 20cm/8in.
Tank size: Minimum 120 x 45cm/48 x 18in footprint recommended.
Water requirements: Relatively unfussy (especially the Electric blue variants). Slightly acidic to hard and alkaline: 6.5 to 8.0pH, hardness 4–16°H.
Temperament: Varies between individuals. Some are outright psychopaths, others shy and timid. Expect aggression.
Feeding: Sinking pellets, tablets, wafers, frozen bloodworm, Krill, cockle, mussel, fresh prawn, flaked pea.
Availability and cost: Pretty commonplace, from £7.50 upwards. Shop carefully, as there are some bad ones available.
Electric blue Ram
These blew on to the scene in a big way around 2009, and have been melting hearts and confounding amateurs ever since.
To start, the Ram — the standard, mass-farmed, colourful and sprightly Ram — was never an easy fish to keep. Fussy for perfect water, exigent for the finest foods, greedy for compatible tank mates; they are surely one of those fish where failures outnumber successes. You don’t even want to think what the wild ones are like.
The Electric blue Ram is more difficult again. For beginners, they seem to tick a lot of the right boxes — they’re small, bright, bold and showy. The problem then is that they end up in undersized, or insufficiently established tanks, with the wrong company.
Whereas many fish have adapted to tanks over generations of farming, Rams retain a lot of their wild demands. They’re hot-house lovers, requiring a temperature over 25°C/77°F and as high as 30°C/86°F, enough to broil most community fish.
Electric blue Rams are also moodier than a raincloud. Get the genders wrong, and they’ll bash each other. Get them right, and they’ll form an amorous bond and bash everything around them, and then possibly each other too. They might even go on to spawn, which
is a treat, as two blue Rams usually breed ‘true’ — their offspring will be as blue as mum and dad.
But of course that does entail getting males and females, and farmed Rams in general have become notoriously hard to sex. Traditional methods, using belly colours and an elongate dorsal ‘whip’ in the males, have become so diluted as to be little more than a loose guide. You’d probably have more luck using astrology or swinging crystals to tell the sexes. In Blues, the belly colour is a non-starter, and elongate dorsal rays are ten a penny in both sexes, so your only hope is to buy either an established pair (pricey) or a small group and await pair bonds to form organically (also pricey).
Getting the right tank is by far the biggest pitfall for Blue Ram keeping. First up, it needs to be bigger than you’re thinking — 60 x 30cm/24 x 12in on the base will house a single pair at a push, but 75cm/30in long is recommended. Anything smaller and you face two problems — fluctuating temperature, and potentially unstable water quality. Note that at the high temperatures Rams thrive at, filter bacteria can become a little sporadic. In the event of a hot spike, filter activity can be seriously compromised. Note also that at higher temperatures, pollutants like ammonia become increasingly dangerous.
Perfecting pH is critical, and integral to Ram success. Wild fish live from around 4.0 to 6.8pH, and though you won’t want those extremes for farmed fish, you still want to be below 7.2pH. Above that, and you’ll see mucus, scratching, poor colours and general malaise.
Warning bells should toll when a Blue Ram on sale looks too bright. Some fish are artificially induced to show their colours with hormones, which can then wear off leaving a drabber fish with a limp immune system.
At the risk of provoking hysteria, note that anecdotal evidence suggests that Blue Rams (indeed, all of the excessive morphs, like Gold, Balloon and Long finned) have a higher susceptibility to disease than normal strains, and as a former retailer of them, I’d be inclined to agree. Whitespot immunity in particular seems low, so have a decent whitespot medication like those from Waterlife or Interpet on hand, just in case.
Scientific name: Mikrogeophagus ramirezi.
Origin: Venezuela, Colombia, Brazil — farmed blue fish mainly from Eastern Europe or South East Asia.
Habitat: Heavily vegetated streams, rivers, floodplains and flooded forest.
Size: To 5cm/2in.
Tank size: Minimum 60 x 30cm/24 x 12in footprint recommended.
Water requirements: Soft, acidic water; 5.0 to 7.2pH, hardness below 8°H.
Temperament: All the rage of a hornet locked up in 5cm of adorable cichlid. Keep away from other cichlids, consider pencilfish and active tetra tank mates.
Feeding: Flakes, frozen Artemia, bloodworm, Daphnia, Cyclops.
Availability and cost: Quite common, price varies hugely with quality, starting from £5 and going up to the £25 mark for magnificent specimens.
Electric blue Acara
If you hate hybrids, you might want to add these to your ‘not to-do’ list right now. While Blue Rams and Blue Dempseys are selectively bred, single species morphs, the Electric blue Acara is apparently not.
To clarify, there are two kinds of Blue Acara. In the first instance there is the standard, naturally occurring Blue Acara, Andinoacara pulcher. Wild types of this fish are gorgeous beyond compare, with streaked blue ‘warpaint’ over their faces, blue flecks and bars down their sides, and striking yellow trim to the dorsal and tail fins. At least, that’s how they were before mass farming overproduced them and turned them into ugly curs with washy colours, stunted bodies and ailments galore.
The Electric blue Acara is quite different. Here, the popular theory goes that ordinary farmed Blue Acara are mixed with Blue Rams to make a new fish. It’s not a natural process, female Blue Ram eggs are fertilised with the sperm of male Blue Acara, giving rise to Electric blue Acara/Ram hybrids. Because of the relative closeness of Rams and Acara, genetically speaking, the new fish are then able to produce offspring of their own.
After that, you can breed Electric blue Acara to your heart’s content, occasionally tossing in fresh Blue Acara DNA to stop inbreeding becoming rampant.
There’s a counterargument by some that the Electric blues are just a line bred mutation, like the Blue Ram, but this seems refuted by people who have bred them with normal Blue Acara and assessed the dominant and recessive traits. The farmers and breeders who sell these fish prefer the lay public (and by extension other farmers) not knowing how these most valued assets are produced, so it’s little surprise that there’s never any clarification when asked.
So here’s a curious thing. If it is a real hybrid, the Electric blue Acara inherits the temperament of neither its Ram mother, nor Acara father, and of all the ‘fake blue’ fish, these are up there as some of the more peaceful. That’s not to say they won’t scoff the occasional small fish, because they do. But anything over the 5cm/2in mark is usually quite safe.
A true Blue Acara can hit around 20cm/8in fully grown, but the electric fish struggle to get close. Most I’ve seen top out around 12cm/4.8in, and females at about 8cm/3.2in. Still, they benefit from a tank of 75cm/30in or longer, and they do gain from being kept away from other cichlids that inhabit the same territory. There will be a degree of aggression at spawning time, but it’s not deeply entrenched.
Sexing Electric blue Acara can be more guesswork than skill, especially when very small. As the fish grow, look for larger, full bodied fish with long dorsal and anal fins — these are likely males. If your fish aren’t too deformed, there are also suggestions that the size of the ‘hump’ on the head is larger in males than females.
As a big downside, these fish tend to have the highest degree of deformities of the Electric blue fish. Look especially to the jaw, which may protrude, slant or fail to open or close properly. Gill covers may struggle to cover the whole gill or close properly (a common problem in overbred fish). Spinal deformity is rife, along with snarled or twisted fins. Shop carefully and reject any fish that doesn’t look pristine.
Quite a few struggle to gain or retain weight, which suggests internal abnormalities, but these may not manifest until later in life.
But, for these problems, a top-end specimen can actually look superb. They won’t be to everyone’s taste and will long have as many detractors as fans, but if they’re your thing, they can make a superb, relatively peaceful addition to a larger community tank.
Scientific name: N/A — likely a hybrid fish.
Origin: Apparently first appeared on an Asian farm.
Size: To 12.5cm/5in.
Tank size: Minimum 75 x 30cm/30 x 12in footprint recommended.
Water requirements: Soft, acidic to slightly alkaline water; 6.0 to 7.2pH, hardness below 12°H.
Temperament: Pretty laid back for a cichlid, usually only aggressive when spawning.
Feeding: Flakes, frozen Artemia, bloodworm, Daphnia.
Availability and cost: Quite common, with prices starting around the £10 mark for small fish. Fork out as much as you can, because you get what you pay for.
Why not add a touch of precious metal to your tank set-up? We look at some sterling subjects for the home aquarium.
WORDS: BOB MEHEN
Sometimes the endless quest for vibrant colour in your aquarium can mean you overlook the more subtle. While bright primary colours are certainly eye catching, sometimes you want something less gaudy, a fish with a little more class — something that doesn’t need to shout “look at me!” to get your attention.
Metallic fish fit this category and can look magnificent, and while a true gold colouration is as rare as the metal, silver is far more common, but certainly shouldn’t be considered as the runners up prize. Who wouldn’t be impressed by glittering shoals of silver flanked fish, or by the mirror sheen silver scales can provide? With a little care in terms of choice you can soon give your tank a silver lining and you won’t have to pay precious metal prices for the privilege.
To the human eye, silver fish are gloriously shiny beauties. Just like the metal, their colouration is an aesthetic attraction to us, but the actual purpose of this precious metal livery is very different. While we might marvel at the lustre of their glittering flanks, potential predators find this mirror finish a confusing problem, making the fish invisible in some conditions, or flash in and out of sight as they catch the light or reflect back their surroundings.
This remarkable camouflage is currently the source of several scientific papers which have discovered that the silver scales not only reflect light but also scramble polarisation. As many fishermen will know, polarising glasses allow you to see through the jumbled reflections on the water’s surface to more easily spot where any fish may be below. In the endless arms-race of evolution, many predatory species have gained eyes that do the same thing, meaning that being simply shiny and reflective is not always enough. The most recent papers on the subject have shown that the scales of these silvery fish have an ‘omnidirectional’ solution to this — light polarisation matching — meaning that in the battle between predator and prey, some fish are staying off the menu by remaining hard to spot. Commercial and military uses for this remarkable ability are sure to follow.
Here are some of our favourite silver fish
Scientific name: Moenkhausia sanctaefilomenae, (Monk-house-eeya sank-ta-fill-oh-men-ay). Size: To 7.5cm/3in.
Origin: Brazil, Paraguay and Argentina.
Tank size: Minimum footprint of 90 x 30cm/36 x 12in.
Water chemistry: 6 to 7.5pH, soft to moderately hard water.
Cost: Around £2 a fish but most shops do deals for groups of five or more.
Some fish seem to have always been around in the hobby and there’s usually a reason for that, be it amazing colour, fascinating behaviour or a peaceful hardy nature. The Red-eyed tetra, Moenkhausia sanctaefilomenae, probably falls into the latter of these categories, but I’d argue it has far more to offer than simply being tough. These are satisfyingly chunky tetras, reaching around 7.5cm/3in, whose bodies are covered in brilliant silver scales, which shine all the brighter thanks to the fish’s signature red eye and bold black tail bar. They make an excellent choice for beginners and will do well in most community tanks as long as the fish they share it with are not fragile enough to be intimidated by the the tetras or large enough to consider them a snack.
A large shoal would look magnificent in a plant rich, clear-water aquarium that mirrors their South American home.
Scientific name: Gasteropelecus sternicla (Gas-tare-oh-pell-eek-uss ster-nick-lah).
Origin: Lower Amazon basin, Brazil.
Tank size: A minimum floor plan of 90 x 30cm/36 x 12in.
Water chemistry: 6 to 7pH, soft water preferred.
Cost: Around £4 each.
Scientific name: Thoracocharax securis (Thor-ah-co-cha-racks sek-ur-riss).
Origin: Amazon river basin, Brazil and Peru.
Tank size: A minimum floor plan of 120 x 30cm/48 x 12in.
Water chemistry: 5 to 7.5pH, soft water preferred.
Cost: Around £5 each.
Scientific name: Thoracocharax stellatus (Thor-ah-co-cha-racks stell-ah-tus).
Origin: Brazil, Peru, Venezuela, Colombia, Ecuador, Bolivia, Paraguay, and Argentina.
Tank size: A minimum floor plan of 120 x 30cm/48 x 12in.
Water chemistry: 5 to 7.5pH, soft water preferred.
Cost: Around £5 each.
Scientific name: Gasteropelecus maculatus (Gas-tare-oh-pell-eek-uss mack-you-lah-tus).
Origin: Central and South America.
Tank size: A minimum floor plan of 90 x 30cm/36 x 12in.
Water chemistry: 6 to 7pH, soft water preferred.
Cost: Around £4 each.
Scientific name: Gasteropelecus levis (Gas-tare-oh-pell-eek-uss lev-iss).
Origin: Lower Amazon basin, Brazil.
Tank size: A minimum floor plan of 90 x 30cm/36 x 12in.
Water chemistry: 6 to 7pH, soft water preferred.
Cost: Around £4 each.
When it comes to silver, the freshwater hatchetfish offer a wealth of choice with most of the commonly seen species (Marbled hatchetfish excluded) being gorgeous, silver sided fish. Perhaps the most metallic amongst them are from the genus Thoracocharax with the unimaginatively named Spotfin hatchetfish, T. stellatus and its close relative the Giant hatchetfish, Thoracocharax securis, both regular imports. These are lovely, big, deep-bodied fish that shine like a new silver penny and are well worth seeking out.
Slightly less impressive in terms of both size and silver shine, but still worthy of a mention are the Gasteropelecus genus of hatchetfish. Gasteropelecus maculatus, G.sternicla and G. levis are all commonly sold under the ‘Silver hatchet’ moniker. These are easily identified from their Thoracocharax cousins due to their smaller size, more shallow ‘keel’, less bright silver colouration and the presence of dark spots or a lateral bar on their sides.
All hatchets are powerful jumpers who use this ability in the wild to escape predation with leaps of several metres well within their capabilities. In the confines of an aquarium this useful survival technique can soon lead to an unpleasant and short lived foray into the carpet pile or a dusty corner behind your cabinet. As a result these fish should only be kept in well covered aquaria and ideally with some floating plants to help prevent them being so easily spooked. The sound of hatchets bouncing off your cover glass is almost as stressful for the aquarist as it is for the fish themselves. They are also all shoaling species so a minimum group size of six or more is recommended.
Scientific name: Metynnis hypsauchen (Met-eye-niss hype-sow-chen).
Origin: Brazil, Peru, Guyana and Bolivia.
Tank size: A floor plan of 180 x 38cm/72 x 15in for a group of adults.
Water chemistry: 6 to 7pH, soft water preferred.
Cost: Upwards of £5 each for juveniles.
This is one of the few iconic silver freshwater species that can be kept successfully in aquaria. These vegetarian relatives of the piranha are restless swimmers and easily spooked, so you’ll need a big tank for them long term. As a result don’t be tempted by ‘50-pence’ sized youngsters unless you have a suitably sized tank waiting; the road to fishkeeping hell is paved with good intentions and promises to upgrade to a larger tank ‘when they grow’.
Check out the sumps and larger tanks in your local store and it won’t be a surprise to see a few dollars down there with the plecs and Oscars returned when they rapidly outgrew their owners’ ambition and budget. Topping out at around 15cm/6in, they will need space to grow and flourish, especially as they do best in shoals like their smaller tetra cousins.
While they naturally tend to live in rivers dense in vegetation, this can be hard to achieve in the home aquarium where most greenery will be seen as a tasty salad. Some people have success with hardy, less palatable plants like Anubias and Java fern, but most have to resort to artificial. They make great companions to midsized catfish and peaceful cichlids like Severum but despite their largely vegetarian diet, small fish might be seen as a protein boost instead of a tank mate.
The almost identical M. argenteus is occasionally seen as well, but those with deeper pockets might like to search out the rarer Red-hook and Black bar silver dollars, Myloplus rubripinnis and Myleus schomburgkii. Note that these fish can deliver a powerful bite so take care when netting them.
Scientific name: Trichopodus microlepis (Trick-oh-pod-us my-crow-lep-iss).
Origin: Vietnam, Cambodia and Thailand.
Tank size: Minimum footprint of 90 x 45cm/36 x 18in.
Water chemistry: 6 to 7pH. Soft to moderately hard water.
Cost: Around £5 each.
If ever there was a fish that deserves a bigger audience than it gets it’s the Moonlight gourami, Trichopodus microlepis. When up against its somewhat gaudy cousins the Dwarf, Pearl or Opaline gourami, it can quite literally pale into insignificance. This is a terrible shame as it is a real Cinderella species, an ugly duckling that will transform into a beautiful swan if simply given the correct conditions and a little time. In most shops these fish appear dull grey, easy to walk by when their showboating brethren are in neighbouring tanks. Settled into a well planted tank with soft, slightly acidic water, they will colour up into a gorgeous lustrous silver sheen, with hints of green and purple, males gaining an orange-red throat and modified ventral fins.
If space allows they look especially magnificent in larger groups provided there is sufficient cover should squabbles ensue.
Silver flying fox
Scientific name: Crossocheilus reticulatus (Cross-oh-chee-lus ree-tick-you-lah-tus).
Origin: Thailand, Cambodia, Laos, Vietnam and southern China.
Tank size: A minimum floor plan of 120 x 45cm.
Water chemistry: 6 to 7.5pH, soft to medium hard.
Cost: Around £8 each.
Many of us employ the services of Flying foxes, Epalzeorhynchos kalopterus or Siamese algae eaters, Crossocheilus sp. to help with a bit of algae control but if you’re lucky and have a closer look in your dealer’s tanks you might spot the rather lovely Silver flying fox. Like so many silver fish, they can be a little grey in the shop tanks, but settled into suitable quarters they are beautiful silver scaled fish, marked with a network of black highlighting the edges of each scale. A bold red eye and black spot on the caudal peduncle completes their livery. Keep them in groups of six or more to see their interesting hierarchical squabbles without the risk of it spilling over into bullying.
Scientific name: Brachychalcinus orbicularis (Brak-ee-chall-sin-us orb-ik-you-lah-riss).
Origin: Suriname and Guyana.
Tank size: A minimum floor plan of 120 x 30cm.
Water chemistry: 5 to 7.5pH, soft water preferred.
Cost: £5 to £8 each.
The appeal of Silver dollars is obvious in terms of their fantastic silver livery but their size can pose a problem for those who can’t fit a suitably large tank in their home. Luckily there are some smaller characin alternatives offering many of the same qualities visually, but without the adult size. The Discus tetra, Brachychalcinus orbicularis, is one such fish that occasionally appears in the shops and is worth seeking out — in monetary terms think of them as a Silver dime! These hardy, adaptable fish may not quite match the mirror sheen of the dollars but are still attractive. Deep bodied when adult, topping out at around 8cm/3.2in, they will fit well into a more manageable 120cm/4ft long tank.
All that glitters…
The Silver or Bala shark, Balantiocheilos melanopterus, is one of the most recognisable species in the hobby and is still commonly seen in many shops as shiny tiddlers. It’s easy to see the attraction as these really are a strikingly handsome fish. Large, gloriously silver scales on a torpedo-shaped body, all topped off with bold black edged fins including a high dorsal and deeply forked caudal which give it its ‘shark’ common name. Add to this a generally peaceful demeanour and active open water lifestyle and it would appear they make the perfect aquarium subject. But sadly this is not the case and the huge majority of these lovely fish live shortened, miserable lives. With an adult size in excess of 30cm/12in, a need for plenty of
company of its own kind and a skittish nature, making them prone to mad dashes around the tank, they really are only suitable for the very largest home aquaria where they can live out their lives without the risk of stunting or constantly braining themselves against the
Another regularly seen silver sided species is the aptly named Tinfoil barb, Barbonymus schwanenfeldii and B. altus. Back in the 1980’s these were the classic companion fish to large cichlids such as Oscars and many tanks we’d now decry for welfare reasons were packed with Tinfoils (and probably a common plec or two). Cheap and readily available as 5cm/2in youngsters, their metallic bodies are offset beautifully by orange-red fins. These fish have phenomenal growth rates and your tank friendly babies will soon be blustering foot-plus tankbusters, no less beautiful but like the Silver sharks, only suitable for massive aquaria.
The Silver arowana, Osteoglossum bicirrhosum, is a majestic, iconic resident of the Amazon with a real prehistoric feel to it. Generally sold as very young fish (some so young they still have their yolk-sac hanging underneath), they are capable of reaching close to a metre in length. They are accomplished jumpers, known as ‘Monkey fish’ in their native range where they have been observed leaping from the waters of the flooded forest to snatch everything from insects to small mammals and reptiles from overhanging branches. Add to this a tendency to suffer from a nasty condition called ‘drop-eye’ when kept in aquaria and you can see why they are totally unsuited to all but the largest aquaria. Avoid.
Another silvery beauty best avoided is the Columbian shark catfish, Ariopsis seemanni. These are a very handsome fish, especially when young. Their smooth, silvery bodies are topped by black, white edged fins, big eyes and flowing whiskers. Typically they are sold as 7.5cm/3in youngsters, all whiskers, fins and effortless charm and ‘cute’ appeal. What often eludes the unwary impulse purchaser is that not only will their new fish grow to over 30cm/12in long and eat anything it can cram into its surprisingly large mouth, but it isn’t really a freshwater species. As adults these fish can be found cruising along the coasts and estuaries of Central America and while occasionally they may push up into freshwater this is usually only the males, taking their mouth-brooded eggs and fry upstream before returning to saltier climes. Oh, and did I mention that they’re venomous?
You can have colourful aquarium fish without having to turn the thermostat up to ‘tropical’ — and the choice is wider than you think...
WORDS: BOB MEHEN
When people think of colourful coldwater fish, the ones that usually spring to mind are fancy goldfish — all eyes, pot bellies and diaphanous flowing fins in bright orange and red.
The fact is though that many of the fish we see swimming energetically in the ‘tropical’ section of our local fish shop are from countries with climates that while perhaps not as varied in temperature as our own island nation, nevertheless still swing high and low with the seasons.
These fish are best described as ‘temperate’ rather than ‘coldwater’, as year round chill will not be to their liking, but if you live in the average, centrally heated UK house then they should thrive, providing plenty of colour without the expense of having a heater constantly operating.
Some more switched on stores have been quick to cotton on to this trend and already have a temperate section filled with some of the hardy regulars often associated with tropical tanks but perfectly suited to cooler climes. The once ubiquitous goldfish, fat fancies aside, have increasingly been shuffled out into the pond section, where they can thrive and grow to their full potential, to be replaced by the aquarium friendly faces of White Cloud Mountain minnows, Zebra danios and Variatus platies to name a few.
We probably all know the amazing toughness and adaptability displayed by that mainstay of the hobby, the Zebra danio, Danio rerio. It’s no surprise these hardy little fish are one of those species regularly recommended to beginners or plonked into new, biologically dead aquaria in the unnecessary practice of ‘fish-in cycling’ — they are tough, adaptable and while not strikingly colourful, offer pattern and movement.
What many people don’t realise is that some of their close cousins have many of the same characteristics, but wrapped up in a more vibrant livery.
Boasting the same pinstripe perfection of its Zebra brethren, Brachydanio kyathit lives up to its common name of Orange-finned danio, with its black barred body set off wonderfully by deep, burnt orange fins, with the same rich colouration spilling over onto their bodies in prime specimens. Like the classic Zebra danio, a spotted form is also often available.
Scientific name: Brachydanio kyathit (Brak-ee-dan-ee-oh kee-ah-thit).
Water chemistry: pH 6.5 to 7.5. Soft to moderately soft water.
Minimum tank size: 80 l/17 gal with a footprint of 90 x 30cm/36 x 12in.
One fish most of us will see regularly, but perhaps not be aware of its temperate potential is the Pearl danio, Brachydanio albolineata. These glossy little fish are exquisite, changing colour like a film of oil on a puddle as their flanks hit the light, moving from metallic blue, then green, violet, pink and gold. In dull conditions they look like a washed out danio version of a Glowlight tetra but given good food, water and lighting they truly shine.
Scientific name: Brachydanio albolineata (Brak-ee-dan-ee-oh al-bow-lin-ee-ah-ta).
Origin: Widely distributed across south-eastern Asia.
Water chemistry: pH 6 to 8. Soft to hard water.
Minimum tank size: 80 l/17 gal with a footprint of 90 x 30cm/36 x 12in.
Arguably even more delightful is the diminutive Glowlight danio, Celestichthys choprae. Like the Pearl, these fish shine and glitter under suitable lighting, with their gold edged fins a real stand out feature. Again their colour changes depending on the light, but the typically warm, pinkish orange hue of the fish’s body is contrasted by a series of blue-black vertical bars.
Scientific name: Celestichthys choprae (Sell-ess-tick-thiss chop-ray).
Origin: Northern Myanmar.
Water chemistry: pH 6 to 7.5. Soft to slightly hard water.
Minimum tank size: 65 l/14 gal with a footprint of 75 x 30cm/30 x 12in.
The Gold ring danio, Brachydanio tinwini, is perhaps the most boldly marked of the ‘danios’ with a series of black spots covering their body and fins, surrounded by a metallic golden sheen, all contained in a small tank friendly adult size of around 2.5cm/1in.
Scientific name: Brachydanio tinwini (Brak-ee-dan-ee-oh tin-win-ee).
Origin: Northern Myanmar.
Water chemistry: pH 6.5 to 7.5. Soft to moderately soft water.
Minimum tank size: 40 l/9 gal with a footprint of 45 x 30cm/18 x 12in.
Those with bigger tanks wanting some real action may be tempted by one of the wonderful species of Barilius, Indian hill trout, occasionally offered for sale. However these are fish with a large adult size, pugnacious nature and surprisingly capacious mouths, best left for larger, specialist tanks with torrent like flow. Consider instead the ‘budget Barilius’ — the Bengal danio, Devario devario. They share the same restless energy and twitchy, active nature of the smaller ‘danios’ and with sufficient space a swirling shoal of these deeper-bodied fish can make a striking display, with their metallic green-blue flanks marked with warm golden blotches. They reach around 7.5cm/3in.
Scientific name: Devario devario (Dev-arr-ee-oh dev-arr-ee-oh).
Origin: Northern India, Nepal and Bangladesh.
Water chemistry: pH 6 to 8. Soft to moderately hard water.
Minimum tank size: 160 l/35 gal with a footprint of 120 x45cm/48 x 18in.
In many tropical tanks tetras rule the roost when it comes to midwater dwelling, shoaling, colourful fish. Mainstays like Neons, Cardinals, Glowlights and Lemons pack aquatic shop tanks with colour. Sadly these are all true ‘tropicals’, which like to bask in the mid 20s°C and will soon look off colour if allowed to dip much below this for long.
There are however a couple of fish shop staple tetras that aren’t adverse to a cool shower, coming as they do from regions of South America where the climate isn’t wall to wall sunshine. Most commonly seen is the stout Buenos Aires tetra, Hyphessobrycon anisitsi. The temperature of these fish’s natural habitat varies considerably and if kept constantly at the high end of their tolerance in aquaria they can live considerably shortened lives at constant fast-forward. Deep bodied and reaching around 6cm/2.5in they sport attractive orange/red fins that set off their overall greenish blue body colouration nicely and the caudal peduncle is marked with a bold black blotch. An albino form is also available which retains the fin colouration but loses all the other colours and markings as a result. They can be ‘nippy’ so choose tank mates with care. Stocking them in groups of ten or more often redistributes these anti-social tendencies amongst their own kind to the degree it is no longer an issue.
Scientific name: Hyphessobrycon anisitsi (High-fess-oh-bry-con an-iss-it-see).
Origin: Brazil, Paraguay, Argentina and Uruguay.
Water chemistry: pH 5.5 to 8.5. Soft to hard water.
Minimum tank size: 80 l/17 gal with a footprint of 90 x 30cm/36 x 12in.
Not as common in the shops, but well worth keeping an eye out for is the Bloodfin tetra, Aphyocharax anisitsi. These are smaller, slimmer fish than Buenos Aires tetra, topping out around 5cm/2in, but share the same bold red finnage against a metallic blue body. Once again, minor aggression can be an issue, so stock them in a generous group. Don’t confuse these fish with the similar looking, but smaller, more delicate and truly tropical Glass bloodfin tetra, Prionobrama filigera.
Scientific name: Aphyocharax anisitsi (Aff-ee-oh-char-axe an-iss-it-see).
Origin: Argentina, Brazil, Paraguay and Uruguay.
Water chemistry: pH 6 to 8. Moderately soft to hard water.
Minimum tank size: 65 l/14 gal with a footprint of 75 x 30cm/30 x 12in.
The Cyprinids (carps and minnows) are the largest family of fish, so it’s not really a surprise that they include many ideal temperate subjects beyond the goldfish.
The stunning Odessa barb, Pethia padamya, is a fish so brightly coloured that due to the manner of its less than conventional introduction to the hobby from Myanmar via the then Soviet dominated Ukraine, it attracted claims that it was a man-made hybrid or artificially dyed. Thankfully all this was cleared up with the discovery of wild populations so we are now able to appreciate them for what they are — one of the best temperate choices of fish available.
Scientific name: Pethia padamya (Peth-ee-ah pad-am-yah).
Water chemistry: pH 6.5 to 8. Moderately soft to hard water.
Minimum tank size: 65 l/14 gal with a footprint of 75 x 30cm/30 x 12in.
When it comes to sporting tiger stripes, there are a plethora of banded beauties among the barbs. While many of these fish are either too belligerent or too tropical to be considered for temperate tanks a noteworthy exception is the handsome Black ruby barb, Pethia nigrofasciata. In the shops these often look like a washed out Tiger barb, but once settled into your tank with a good mix of sexes, males develop a deep purple-black body colour fading to ruby red around the head, speckled with metallic silver scales, like the sky at night. Females remain simply boldly striped, but their presence encourages the male’s best colour and courtship displays.
Scientific name: Pethia nigrofasciata (Peth-ee-ah nig-row-fash-ee-ah-ta).
Origin: Sri Lanka.
Water chemistry: pH 5.5 to 7.5. Soft to moderately hard water.
Minimum tank size: 65 l/14 gal with a footprint of 75 x 30cm/30 x 12in.
If you’re a sucker for goldfish but don’t have a vast tank or space for a pond then the Rosy barb, Pethia conchonius is the obvious choice; all the charm and colour of the goldie but with an adult size seldom exceeding 8cm/3.2in. Selective breeding over decades means a range of colour forms are now seen, as well as a flowing finned ‘comet’ type, which is far removed from the wild fish but still very popular.
Scientific name: Pethia conchonius (Peth-ee-ah con-cone-ee-us).
Size: 6.5–9cm/2.5–3.5in. l Origin: Pakistan, India, Bangladesh and Nepal.
Water chemistry: pH 6 to 8. Slightly hard to hard water preferred.
Minimum tank size: 80 l/17 gal with a footprint of 90 x 30cm/36 x 12in.
A barb that has taken the hobby by storm in the last decade has been the Red-lined torpedo barb, Sahyadria denisonii. Their striking, shark like silhouette, attractive, bold colouring
and peaceful nature has seen them rise to the heights of aquarium ubiquity alongside Neon tetras and angelfish. However, what is not so well known is the fact that these fish aren’t best served in the permanent summer of tropical tanks, where their metabolism is on fast-forward and their lifespan shortened as a result. In the temperate aquarium they will keep pace with seasonal changes and live longer, more natural lives. As with most barbs, they do best when kept in larger groups and look especially impressive holding station with just a sporadic flip of
their forked tail against the steady current of a flow pump, breaking formation occasionally to snatch a passing morsel.
Scientific name: Sahyadria denisonii (Sa-hee-ad-ree-ah den-iss-own-ee-eye).
Size: Around 10cm/4in.
Origin: Southern India.
Water chemistry: pH 6.5 to 7.5. Moderately soft to hard water.
Minimum tank size: 160 l/35 gal with a footprint of 120 x 45cm/48 x 18in.
Sub-tropical substrate huggers
Once you’ve packed the upper layers of your tank with colourful barbs, danios or tetras you’ll probably want to balance things out with some bottom dwelling species. There are plenty of candidates to be plucked from the ‘tropical’ section that will appreciate cooler conditions.
My personal favourite is the comical Panda Garra, G. flavatra. These boldly banded beauties are great algae munchers but should never be bought for simply this purpose. They do best in groups of five or more where their hierarchical tussles make fascinating viewing.
Scientific name: Garra flavatra (Ga-raa fla-vat-raa).
Origin: Western Myanmar.
Water chemistry: pH 6.5 to 7.5. Soft to moderately hard water.
Minimum tank size: 80 l/17 gal with a footprint of 90 x 30cm/36 x 12in.
The classy looking Yo-yo loach, Botia almorhae, is another unexpected temperate treat. These handsomely marked fish get their common name from their juvenile markings which appear on many fish as a series of black-brown y’s and o’s over a cream background. As the fish matures the patterning breaks up to a more regular reticulation, but is still lovely. Like most Botiid loaches they are social and should be kept in groups of at least five to prevent the smallest fish being picked on.
Scientific name: Botia almorhae (Bow-tee-ah al-more-ay).
Origin: India, Nepal and Bangladesh.
Water chemistry: pH 6 to 7.5. Soft to slightly hard water.
Minimum tank size: 160 l/35 gal. with a footprint of 120 x 45cm/48 x 18in.
If you’re after a real character fish for your tank then look no further than the Red-spotted goby, Rhinogobius rubromaculatus. These charming little micro-predators are always on the look-out for something to eat. Males in breeding colour are gorgeous, a lovely soft powder blue covered in scarlet spots with the edges of their fins highlighted in bright white. Females are more washed out, with pale yellow fin edges but without a mix of the sexes you won’t see the fantastic head shaking, ‘gaping’ displays as males spar with each other and try to woo interested females. These gobies require good levels of dissolved oxygen and are evolved to live in areas with strong water flow.
Scientific name: Rhinogobius rubromaculatus (Rye-no-go-bee-us roo-bro-mak-you-lah-tuss).
Water chemistry: Moderately soft to slightly hard water.
Minimum tank size: 50 l/10 gal with a footprint of 60 x 30cm/24 x 12in.
Few tanks are complete in my book without a catfish or two. Many of us will know that the Peppered cory, Corydoras paleatus will get along nicely in temperate tanks.
Less well known is that the Three-lined cory, Corydoras trilineatus, (often sold as C. julii) is also well adapted to cooler water.
Scientific name: Corydoras trilineatus (Coor-ee-door-ass try-lin-ee-ah-tuss).
Origin: Amazon basin in Peru, Brazil and Colombia.
Water chemistry: pH 6 to 7.5. Soft to slightly hard water.
Minimum tank size: 50 l/10 gal with a footprint of 60 x 30cm/24 x 12in.
Add to this their flashy big cousin the Bearded cory, Scleromystax barbatus, and you have a couple of nice alternatives to Peppered corys.
Scientific name: Scleromystax barbatus (Ss-leh-row-miss-tax bar-bay-tuss).
Origin: South Eastern Brazil.
Water chemistry: pH 5.5 to 7.5. Soft to slightly hard water.
Minimum tank size: 50 l/10 gal with a footprint of 60 x 30cm/24 x 12in.
For larger tanks or bigger, more robust midwater fish that might intimidate corys, look instead at those seemingly indestructible, animated armoured sausages ‘Hoplos’, Megalechis thoracata, which are easily able to deal with bolshy barbs and cooler temperatures.
Scientific name: Megalechis thoracata (Mega-lek-iss thaw-a-cart-ah).
Origin: Brazil, Peru, Trinidad, Guyana, Martinique, Venezuela and Paraguay.
Water chemistry: pH 5.5 to 8. Soft to hard water.
Minimum tank size: 160 l/35 gal with a footprint of 120 x 45cm/48 x 18in.
Cool — but not cold!
While all these fish can make a fantastic display at lower than tropical temperatures it is vital they don’t get too cold. Even in a modern, centrally heated house things can cool off considerably at night so adding a heater, set at the lower end of your chosen fishes’ range is a wise precaution. Similarly, just as some of these fish will suffer if kept permanently at the high end of their tolerance, they will not all appreciate being kept at the bottom end constantly — who wants to live in a permanent state of winter?
Consider creating an artificial summer or dry season period where the temperatures are elevated to the upper end of the fishes’ range — in the majority of UK houses this will happen naturally each summer even given our often less than tropical weather!
Kuhli loaches get a domestic makeover and some new housemates in a handful of easy to copy steps…
WORDS AND PHOTOGRAPHY: NATHAN HILL
Steve Hunt’s Kuhli loach was in dire straits. The nano tank it had called home had been a present for Steve’s daughter, but it was woefully small. A curve-fronted little all-in-one lump of barely 30l/ 6.6 gal, it had become tired and grubby, hidden away in a corner, decrepit and embarrassing.
My original offer was to overhaul the tank, revamp it and make it shiny once more. The centrepiece of the tank — the crowning achievement — was to be a tubular ‘loach hotel’. The idea was simple. A bundle of pipes was to be constructed into a large pyramid, with all the tubes facing the same direction. Any mixture was to be used — ceramic, plastic, old hose or miscellaneous. They were to be glued together, and then given a thatched roof of Java moss, strategically glued at key points. That was the plan.
Then one morning a 102cm long Ciano Emotions Nature Pro tank turned up for review and blew all those early plans out of the water. I offered it to Steve to break in for me, and we went back to the drawing board. ‘How about a luxury, open plan apartment,’ I suggested, ‘with plenty of crevices and open spaces?’ Steve was sold on it.
With the added swimming area, we plumped for a streambed tank with extra inhabitants. Kuhli loach are handsome but shy, and even a dozen or so in this tank could prove hard to spot. Give them too many hiding spaces and you’ll never see them. Don’t give them enough and they’ll never become confident enough to show as much as a whisker. Many a tank has ‘lost’ its Kuhli loach for years at a time, only found again when the tank is eventually stripped.
Kuhli loach are Malaysian fish, so we wanted a tank with plants from that part of the world. That meant two easy targets appeared straight away — Cryptocoryne and Java fern.
For tank mates, we needed something that could get on well with low flows. Kuhli loach hate high flows (which is handy, as the outflow of the tank’s filter is pretty mild), coming from slow moving, leaf-littered and often darkly acidic waters. A little head scratching and we came up with the idea of danios. While not entirely geographically correct, Brachydanio kyathit (from Myanmar) has enough overlapping requirements of water (soft, acidic, slow flowing) and temperature (best under the usual 25°C/77°F tropical catch-all) to live in harmony here. And given that they make their living at the middle and surface of the water column, they’d provide plenty of movement while the loaches were out of view. It was optimistically hoped that they might even act as ‘dither fish’, helping to boost the confidence of the loaches and encouraging them to come out more.
We were pleasantly surprised when they did.
Here's how the tank went together...
1. The cabinet was assembled and put into place with the tank on top. We placed it against a wall in close proximity to power sockets, and as we were on a ground floor, there was little worry about finding floor supports and positioning the tank across them. Once in place, a spirit level was used to check that it was sat squarely and evenly.
2. The filter was assembled. The Ciano filter uses a mixture of cartridges and foams. When constructing a filter, always ensure that things like carbon pouches are quickly rinsed, and that any media sealed in packaging for transport is liberated from it. Many a tank has failed because the biomedia was trapped in a plastic bag when everything was switched on!
3. Pre-washed silver sand is added and shaped into a mild slope, and the two largest foundational rocks added. The rocks cover a maximum of two-thirds of the tank for both pragmatic and aesthetic reasons — an open area allows for debris to accumulate and be removed more easily than if the whole base is decorated.
4. A third stone is added (and note the way that it has been placed, allowing for a broad cavern underneath) and a large chunk of bogwood added for both height and to reach out into the ‘open’ region. At a later stage, the wood may be used to house plants such as mosses or Java ferns.
5. Large Java ferns are added. I’ve taken the unusual step of keeping them in their pots and adding them to the base of the tank instead of tying or adhering them to wood. The pots are not placed deep in the substrate, allowing the root structures to still uptake nutrients. Planting Java ferns into the substrate can cause the roots to suffocate and die off.
6. Mixed Cryptocoryne are removed from their pots, have their roots trimmed and tidied, and are planted. Crypts are notorious for ‘Crypt melt’ after transit, and we kept them in large clumps for the first few weeks to see how they settled in. Once happy they weren’t going to die, we later divided them up into smaller plantlets and spread them over a wider area.
7. The tank is filled with water, using a colander to stop the inflow from stirring up the substrate, and everything is turned on. As the heater is not visible (it is hidden inside the filter), monitoring with a thermometer and adjusting over the following days is essential to get to the right temperature. We ran this tank at 23°C/73.4°F.
The tank was matured using a mixture of ammonia, Evolution Aqua’s Pure Aquarium, and pre-seeded media hijacked from another aquarium. The cycle was rapid, just a couple of weeks before we were able to add fish, but this stage of the tank’s life requires scrupulous water testing to ensure that ammonia and nitrite levels are being controlled by the life support system.
Scroll down for a video of the finished set-up.
The big stones used here were bought from a garden centre as rockery stones. Though dusty, we tested them with a little hydrochloric acid to see if they ‘fizzed’ and they did not, meaning that they do not contain any water-hardening calcium carbonate.
To float or not to float…
The wood we tried here was dense, perhaps the densest I have used in a tank. On this rare occasion, it did not require prior soaking, but you will likely find that any wood you use will need to be placed in a bucket of water for a week or two before use.
The rounded rocks we used could easily be replaced by large flint cobbles. I’d be wary of using one of the large ‘resin type’ fake stones in this role, as these are hollow and you’ll soon have more Kuhli loaches inside it than out of it.
For wood, any of the hardwood types would be suitable. Oak or Beech would offer a tangled, fine-branched effect, while the aquarium staple of Mopani could bulk up an area in place of
Kuhli loach, Eel loach — call ‘em what you will, but they’re one of the best wriggly beasts you’ll meet. Intensely shy, masters of hiding and burying, and diehard fans of bloodworm, just pray you never need to catch them in a hurry. They are far better at swimming than you will ever be at using a net…
Scientific name: Pangio semicincta (Pan-ghee-oh sem-ee-sink-tah).
Habitat: Slow moving forest streams and static bodies of water, often acid-soaked and discoloured. Little, if any flow.
Water requirements: Soft, acidic water; 4.0 to 7.0pH, hardness 1–8°H.
Feeding: Loves frozen and live foods like Cyclops, Daphnia, Tubifex and bloodworm.
Temperament: The most peaceful fish there is.
Availability and price: Widely available, starting from around £2.50 a fish. Buy in bulk for reduced prices. We bought 12 specimens for this set-up from the Waterzoo in Peterborough.
Orange finned danio
These are small fish that need a big tank, like many of the ‘danio’ varieties. Once settled, this has to be the brightest of the family, with its fiery orange flanks. Kyathits prefer tanks with plenty of plants, and if you can’t get lots of greenery then at least go for a dark substrate, otherwise you’ll end up with pale fish that hide their best colours away. Invest in some colour-enhancing foods and Calanus to keep those markings intense.
Scientific name: Brachydanio kyathit (Brak-ee-dan-ee-oh kye-ath-it).
Habitat: Slow moving streams with heavy planting at the banks.
Water requirements: Soft, acidic water; 6.0 to 7.5pH, hardness 1-8°H.
Feeding: Will take flakes, but also offer plenty of frozen and live meaty foods like bloodworm and Daphnia.
Temperament: Incredibly peaceful and a perfect community fish.
Availability and price: Increasingly available, with prices starting around the £2 mark.
How’s the learning curve coming along for you? Nathan Hill looks at some of the most common blunders made by aquarists — both new and experienced!
I’ve kept fish for 35 years now, and every week I learn something new. The worst mistake any of us can make is to think that we know it all, and that we have nothing further to pick up.
For some of us the curve is gentle. For others, it’s a hairpin, leading to costly mistakes, dead fish, and frustration. Some aquarists may find themselves snarled up against a problem that requires thorough investigation. But there are also folks who are doomed to make life hard by overlooking some simple, easy to rectify measure.
Here’s a breakdown of some of the most obvious blunders and gaffs that fishkeepers — both old and new — are prone to making. Avoid them at all costs...
Imagine I trap you in a bathtub, but don’t let you out to use the toilet. The more I feed you, the sooner that bathtub’s going to turn foul. It’s just the same with fish.
Unless you’ve a demanding predator, then your fish (and your filters) will benefit most from small, regular feeds instead of big, random splurges.
Offer a little bit of food and see if they can eat it all in 30 seconds. If they nail it all in ten seconds, you’re not adding enough. If it takes them a minute, you’re adding too much. The trick is to find that magical quantity that will allow a 30-second feed at a time, and then add that amount three times in a row, allowing for a 90-second feeding time in total. Remove any uneaten food afterwards with a net.
I’ve spent enough time curled up with stomach cramps to learn this one for all of us. Do not suck hoses to start syphons. You’ll get ill. It’s that simple.
So how do you start a syphon? Consider buying a gravel cleaner with a non-return valve in it. That way, you just bounce the device up and down in the tank, and the water will flow out for you. Alternatively, get a model with a hand-powered pump to start it. Or splash out and get a battery powered model to start the water movement off for you.
Just do not suck on the end of a pipe, I implore you.
Mistaking pollution for disease
Most of us are savvy about this, but some people still refuse to accept that they might be directly responsible for the problems in their fish.
Water issues and illnesses go hand in hand, and it’s rare for aquarium fish to go down with disease if there’s no pressing issue of water quality. The symptoms of the two camps look very similar. Gasping, lethargy, dashing, slimy skin, cloudy eyes, poor colour — all of these are more likely to be the result of pollutants than pathogens.
Test first, reach for the medicines later.
Having shoals that are too small
Some fish are destined to do badly by virtue of being constantly nervous. Shoaling fish are gregarious by nature, and their whole life cycle may depend on their interactions with others.
In the wild, barbs and tetras may live in shoals of hundreds at a time. In those shoals will be complex hierarchies, social ties and breeding opportunities. When kept as three individuals in a tank, all of this innate social programming is redundant.
That could mean shy fish, hidden away, refusing to eat and slowly starving. Or in the case of others it may lead to fin nipping, as fish try to interact with different species as they would their own kind.
Always buy as many of one kind of shoaling fish as you can afford or accommodate. Mixed shoals, and the pick-and-mix option might be great for bags of Haribo, but this approach won’t work with sensitive animals.
Trapping sand and gravel in algae pads
I’ve seen acrylic tanks reduced to tatters in seconds, simply through the use of a badly maintained algae pad.
A piece of grit or gravel is like a diamond cutter once you start rubbing it against the front pane, so make sure you check your pad before and after each use. Rinsing beforehand is essential, and inspect closely. It may sound excessive, but when you’re cursing that 20cm/8in gash in the front of your tank, you’ll understand why you should have done it.
Also, as a pro tip, rinsing algae pads after use is a great way of controlling any pathogens that they might collect.
Washing foams in tapwater
If you’re new here, then this will be one of the most important things to take away from the magazine. Do not wash your filter foams under the tap. The foams contain bacteria, and those bacteria are helping to keep your fish alive by converting harmful wastes. Treat the foam more gently than a newborn puppy, bathe it softly in old tank water, and never, ever expose it to any kind of disinfectant.
Not cleaning pipes
Ever had that moment where you’ve cleaned your external filter, spruced up the foams, plugged it all back in and been greeted by a puff of white and brown bits blasting through your outlets? Annoying, huh?
Biofilm develops in lengths of hosing, and the on/off action during maintenance will loosen it. Clear pipes will develop algae, and trap mulm, too. Eventually these build ups can impair flow, so they need addressing.
Clean your pipes every other time you open the filter. You can buy brushes to get inside them, but I’ve always found that a purge with hot water and a funnel down the sink does the job just as well.
Using one net to catch fish
A net will cost you between £1.50 and £3. Buy two of them.
Catching fish with a single net is stressful for the aquarist and the fish. Professionals struggle, amateurs make a total ham of it. Use one net as a sheepdog to encourage the fish into the other.
Some experts claim success with different coloured nets, using a small, blue net to chase fish into a larger, green one. Others insist that fish are easiest to catch with red nets.
More importantly, get the right size. For average, 2–7.5cm/0.8–3in fish, opt for a net with a 15cm/6in width. Tiny nets are of little use for anything bigger than slow fry, while bigger nets may seem intuitively better for catching, but in practice turn out to be slow and cumbersome.
Also, if dealing with bracer bars or odd shaped tanks, bending the net can make the job considerably easier.
Buying ‘cleaner’ cats and ‘algae eaters’
Your catfish don’t clean their tanks any more than my dog hoovers my floor. Most of them have more specialist diets than the tetras and barbs swimming above them, so scraps simply will not do. Emaciated looking catfish are unlikely to be suffering internal parasites, but very likely to be undernourished. Find out what they eat, and supply it.
By the same token, don’t assume that any fish with a suckermouth is a herbivore. Many of these species, all too often euphemistically labelled as ‘algae eaters’ are devoted carnivores that prefer snail meat and other aquatic inverts, while others grow huge. Review all fish on a case by case basis, and provide the diets they need.
Medicines, tonics, salt — everything! We are a nation of overdosers when it comes to fish, without realising that too much can be more harmful than not enough.
Some tank manufacturers exacerbate the problem by stating displacement volumes instead of actual volumes. So if you buy a tank advertised as 100 l/22 gal, it may in reality hold only 85 l/19 gal of water once you’ve added the substrate and decor.
Calculate easily, and do it for yourself. Measure the length, width and water depth
in centimetres and then get a calculator. Follow the calculation below and you’ll be fine: Length (cm) multiplied by width (cm) multiplied by water depth (cm). Divide that number by 1000 and you have the volume. Multiply this number by 0.9 to deduct 10%, to account for displacement due to substrate and decor, and you have the treatment volume.
For a 120 x 45 x 45cm tank:
120 x 45 x 45 = 243,000.
243,00 divided by 1000
= 243 l.
243 l multiplied by 0.9 = 218.7 litres of water to be treated.
Assuming all tropicals should be kept at 25°C
The word ‘tropical’ has a connotation with being a very particular, set temperature.
The reality of the world is different. Some tropical fish come from high altitudes, or low ones, where the temperature can be far from 25°C/77°F. Some live in open, sun-exposed areas, while others huddle under dense, shaded canopies. Some live in deep holes in the ground, or caves.
Finding out where a fish is from and providing the right temperature is essential. Too cold and it will struggle to grow, and will have weak immunity. Too hot and it will struggle to retain weight, or may die outright.
A temperature of 25°C/77°F is a fair balance for many popular species, but even very common fish like Neon tetra like things cooler, and live shortened lives in hotter climes.
Thinking all snails are bad
The presence of millions of snails is bad, but the snails themselves are amoral, and often helpful agents, just exploiting an easy food source.
There’s a balance. Snails eat debris and detritus in a tank, along with algae and dying plants. They love it. They thrive on it.
The simple equation is the more snails you have, the more food there must be available for them. And the more food they have means that you as the owner and cleaner of the tank are doing something wrong.
Five point snail-eradication plan
1. Clean the gravel thoroughly. Remove uneaten food and mulm.
2. Go through your plants and remove any struggling leaves.
3. Review feeding levels. Are the fish leaving food uneaten?
4. Purchase a snail trap, or use a saucer with snail bait.
5. Purchase some Assassin snails to eat the stragglers.
DO NOT be tempted to:
- Add snail-eating fish like Clown loach.
- Resort to harsh snail killing liquids without addressing waste
- levels first.
- Kill snails and leave them in the tank to decompose.
Taking pity on runts
We all love to nurture the weaklings from a brood — it’s a part of our inbuilt nature as humans to take sympathy on small, struggling things. Look at why puppies and kittens are so popular.
With fish, you might be taking on an impossible task. A fish that lacks fins and cannot swim properly may have a terrible quality of life, may be pecked by tank mates, or may miss out in the competition for meals.
Or you could be inviting disease in to the home. Some deformities can be caused by viral tumours, internal parasites or bacteria. What might look like a cute one-off quirk in a store
tank could be a festering hamper of illness waiting to strike your aquarium.
The sad fact is that fish often have so many young to account for the runts, also-rans and outright failures. When you keep one of those runts alive, allow it to reproduce, and pass on the young, you’re just subjecting others to the same problem later down the line.
What to look for when buying fish:
- Well-formed body and fins. No splits or tears.
- Both eyes intact.
- Mouth opening and closing correctly, no twists in the jaw, no over- or underbite.
- Gill covers that do not leave any of the gill exposed when closed.
- Straight spines, no kinks or ‘S’ shapes.
- No lumps or bumps.
‘Growing’ plants in gravel
This is up there with buying houseplants as aquarium plants. Keep a plant badly, and it’ll die. Before it does, it’ll feed a plethora of snails and release all manner of waste into the water.
For most species, gravel is not conducive to growth. Potted plants may tolerate gravel for a while, but eventually even they will find the substrate too harsh.
If you are stuck with gravel in the tank, you can at least make ‘plant boxes’ using a margarine tub. Fill the tub partway with plant friendly substrates, place it in the tank wherever you want growth, plant greenery into it, and then hide it by covering with a thin layer of the same gravel in the rest of the tank. The plant roots will be happy, and observers will be none the wiser.
A tank in a living room can be surrounded by hazards. Minimise the risk to your fish by knowing the chemicals that can be toxic to your fish.
WORDS: NATHAN HILL
Today, somewhere in the world, someone will be looking at a tank full of dead fish and scratching their head, unable to ascertain why.
It might be something catastrophic that’s happened in the tank, a crash of the filter, or the result of a stuck, overzealous heater.
A lot of mysterious deaths are never solved, because hobbyists focus solely on what’s going on in the tank, and not what’s happening around it. The problem is, extraneous factors can be just as – if not more – deadly than anything that happens within.
If you weren’t aware of the outside influences that can cause a wipe out, then now’s the time to learn. You might be closer to devastation than you think.
Not the obvious problem that people imagine it to be, but sound can cause acute or chronic stress in fish, weakening their immune systems and leaving them wide open to infection. In extreme cases, a sudden, loud noise can be enough to shock a fish into an abrupt and immediate death.
Anything that impacts against a tank has the power to kill. Fish partially detect the world around them through their lateral line system, a sensory accessory that lets them detect the tiniest of changes in water pressure. Subjecting them to a sudden shock like a slap against the glass is the fishy equivalent of me firing a shotgun right by a person’s head. Children are among the worst culprits for tank slapping (which is why you hear so many of them being told off in aquatic stores), but pets and slamming doors can be just as bad.
The rumbling bass notes of a loud TV or stereo are enough to drive terror into most fish, so any tank situated by a speaker is prone to problems. Try to keep the home cinema and the aquarium in separate living quarters.
The air we breathe
The oxygen in your tank comes from the air around it. Subsequently anything in the air nearby can get into the water and cause problems.
Worse still, water is great at attracting airborne pollutants, and collecting and concentrating them. Your lounge might be an atmospheric soup of chemicals, and if it is, then it’s a safe bet that the levels in the water are even higher!
Some day-to-day chemicals are worse than others, and some (if you read the packaging) will even point out that they’re not safe to use in the vicinity of fish tanks. If they do, then take their advice.
Fleaspray is lethal to fish. An active ingredient — permethrin or pyrethrin — is one of the most potent fish killers you’ll find (and it’s not great for humans either). Any recently sprayed pets should be kept well away from even the rooms where fish tanks reside.
Air fresheners are all too often little bundles of death where fish are concerned. The very chemicals that bring fresh smells are frequently toxic to fish at even low doses. Spray fresheners can provide sudden acute poisoning, while slow release plug-in fresheners release chemicals that gradually accumulate. If the packaging doesn’t claim it’s safe with fish, then assume it isn’t.
Cigarette smoke is heaving with toxic nicotine, and though I’ve found nothing to verify it, I imagine that e-cigs could do the same. Some fish can be surprisingly tolerant (like goldfish) while marines are incredibly fragile. I’ve seen a whole reef tank wiped out
by a single cigar before.
Deodorants and perfumes are the reasons that many tanks in adolescents’ bedrooms can fail. Always spray them in a different room to your tank, and if perfume has been applied to wrists, then keep your hands out of the tank.
Polish is a tricky one, as nobody wants to live in a grotty room. Airborne polish is a huge issue, while impregnated on a cloth is less so. Spray the polish on to your cloth elsewhere in the house, and then use it to wipe in the tank’s vicinity, but be vigilant for signs of stress and poisoning in fish when doing so.
Paint and varnish can be as bad as each other. Don’t think for an instant that you can just cover the tank and paint around it. You’ll need to move everything out while you refresh your walls or skirting boards.
Hand soap and hand sanitising gels are great for hygiene, but it’s essential you use them after going into the tank, not before. I’ve even known aquaria wiped out by people who had been doing the dishes and still had soap residue on their skin.
If you use the same bucket to clean the car, windows, floor and aquarium, you’re asking for trouble from the cocktail of deadly chemicals clinging to the bucket’s sides — even if you rinse it out.
Insecticides may be less of an issue for fish, but outright lethal to inverts like shrimps. To leave some Eastern countries, plants need to be sprayed with chemicals that kill hitch hiking bugs and beasts. New plants that haven’t been soaked or rinsed appropriately are a common cause of shrimp deaths, making their flesh turn opaque before they die. With some insecticides, a rinse of your new plants won’t be enough, and instead they may need several days of soaking.
Fish medicine can be alarmingly toxic. Too many newcomers (and quite a few old hands) think ‘if one drop will fix the disease, two will fix it in half the time!’ Medications are designed to work at a set dose, usually just enough to be lethal to pathogens, but not quite lethal enough to harm fish. Overdoses can cause major organ damage, clubbing gills and ravaging kidneys.
Always carry out water tests away from the tank and never place the sample on top of the aquarium while you wait for the results. A spillage could prove deadly to your fish.
Salt should be handled with care. Used to excess it will accumulate in the water, and can start to dehydrate fish. It may sound odd, but it happens much more than you might think.
How to spot a case of poisoning
Symptoms can vary between fish, as well as pending which chemicals have affected them, but there are a few general things to watch out for.
Enhanced colours can often be associated with toxins in the water, as can typical stress markings such as dark bars or spots on the body.
Gasping at the surface can be from water-borne problems like ammonia, but it can easily be an introduced chemical that’s irritating the gills.
Lethargic behaviour and resting in one spot may be a natural behaviour for some fish, but when all are doing it, you’ll need to investigate.
Erratic behaviour, flicking, or trying to jump from the tank can be from a sudden change of pH, but it can also be an escape reaction from something nasty that has gotten in to the water.
How to fix it
If you don’t know the mantra already, then recite it until it’s firmly in there. “The solution to pollution is dilution!” Now say it fifty times in a row.
Water changes are essential in suspected poisoning cases. The sooner you can dilute down the offending chemical, the better. In mild cases, a course of 20% daily changes over a week will help, while outright emergencies may require 50% or more of the water in one go. There are no hard and fast rules, but remember that if you take out more then you also risk upsetting the filter.
Some media will help, especially carbon. For a quick removal of many unknowns, keep an Arcadia Polyfilter handy. They’re not cheap, and they’re quite short lived, but they can be the difference between dead fish and live ones in a crisis.
Of course, the best thing is to not poison your fish in the first place, so the moment you suspect it has occurred, you’ll want to snoop about the room and find out what’s causing the problem — then eradicate it!
Make the most of the autumn season by collecting leaves for use in your aquarium and discover the benefits to both your fish and your bank account.
WORDS: GABOR HORVATH
When, quite some time ago, I inherited a small group of Wine-red Betta, B. coccina, I didn’t know what a task and responsibility I had taken on. After a quick search of the available literature, I realised they originated from Asian peat swamps and prefer soft and dark — almost black — waters with leaf litter.
As I’d never had a fish before with similar requirements, I assessed my options. The first was to buy a ready-made black water tonic to add to their tank. The second solution was to get some imported Catappa leaves and use them to recreate the natural habitat.
The final, third option was to collect fallen leaves from a nearby forest and use those instead. This latter choice was also the cheapest and as I was on a very tight budget at that time, I opted for gathering oak leaves. Fortunately, I had a week to prepare the tank for the Betta coccina, so when they arrived I greeted them with perfect water conditions.
Since then I have kept several other leaf-litter-loving fish and — especially since becoming involved with shrimp keeping — I have learned a lot about the different leaves and their potential uses in the aquarium. So, I’d like to offer you some guidance on choosing and using them in your fish or shrimp tank.
The benefits of leaves
Many of our favourite fish originated from waters flowing through dense vegetation and forests. The constant supply of falling leaves will colour the water tea brown, sometimes almost black. One of the culprits of this is an organic compound called tannin, which can be found in different quantities in most of the dry leaves. It is also a weak acid, which can reduce the pH of the water. The tannin is most effective in very soft waters, as the buffer capacity of hard waters can easily neutralise its acidity. Most of the black water species require soft water anyway, so with a carefully selected leaf you could achieve two goals at the same time: a nice, dark water and low pH without a need to use chemicals.
As well as tannins, some leaves also contain other organic compounds that could tackle fungal and bacterial infections without the need to use medications. Catappa (also known as Indian almond or Ketapang) leaf is widely used by fish farmers and exporters in the Far-East to reduce stress and cure diseases. The leaves of the Walnut tree — if collected green and then dried — have similar effects and are very popular among shrimp breeders.
Leaf litter can also help shy species, such as Liquorice gourami, Parosphromenus sp., to settle down easier. It provides perfect places to hide, especially if you are using naturally dried, curled leaves and not the flat-packed commercial ones. Even cory cats love to play hide and seek among them, often choosing the larger leaves for depositing their eggs instead of the sides of the aquarium glass.
And we mustn’t forget about the use of leaves as decor. While not everyone’s cup of tea, certain biotopes require leaf litter. If you don’t want tea-coloured water, choose a leaf that will not colour it (or boil and soak them for a while before use). For decorating reasons you have a wide choice of large (Plane tree, Turkey oak, Catappa), medium (Oak, Hazelnut) or small (Beech, Silver Birch, Hornbeam) leaves.
Leaves can play an important role as a grazing ground for young and adult shrimp, and Mulberry is widely known as an excellent shrimp snack. The biofilm growing on the decaying leaf surface will also be appreciated by the fry of several fish species, acting as their starter food. Fresh leaves of several plants — for example blanched Spinach, Dandelion and Stinging nettle — can also be used to feed fish and shrimp, although in this article I will concentrate on ligneous (woody) plants only.
Most aquarists in the UK have heard of the Catappa leaf and some are familiar with its beneficial effects. If asked about British tree species useful for aquaria, most will probably mention Oak or Beech, but few will have tried any others.
A couple of years ago I met Gabor Csepanyi in Hungary, who became an “advocate” of using leaves and other parts of domestic plants instead of imported ones. He believes it is a more eco-friendly and also wallet friendly option. A discussion with him and the results of Istvan Toma’s research investigating the effect of different leaves on water parameters, have opened up my eyes to see a world of local leaves with possibilities too good to miss.
So get out there, and get collecting!
Did you know?
Autumn is the perfect time to top up your leaf stock. By this time all the unwanted compounds (sap, protein, chlorophyll etc.), are removed from the dying leaves by the tree. The tannin concentration on the other hand is increased — it can be 3–4 times higher than in the green leaves.
The dos and don’ts of collecting leaves
- Don’t collect leaves from a roadside, or other polluted areas. If you live in a big city, it’s time to visit the countryside!
- Do ensure that no chemicals have been used if you are planning to gather your stock from a maintained area (like castle parks or botanical gardens). Always check with the management first. The same applies for trees located near
- farm land.
- Do pick only healthy, undamaged leaves — watch out for bite marks, discolouration or deformations.
- Do try to collect the leaves as soon as they have fallen (try to beat the rain) to avoid the bleaching out of the valuable compounds.
- Don’t collect overwintered leaves in the spring, unless you only plan to use them as decoration (but even then they will not last for long).
- Do dry the leaves as soon as you can after collection — just spread them on a tray over a layer of paper kitchen towel. I prefer curled up leaves, but if you want flat ones you need to use a press (a couple of books would do). When fully dry store them in a paper bag or box in a dry place.
Leaves with special properties
Some leaves should be picked green and then dried for storage. In this state they can store valuable nutrients or useful organic compounds, so they are mainly used as food or as an antibacterial and antifungal water treatment. But a word of warning: be very careful with the dosage of green dried leaves, as overdosing them can lead to cloudiness and a deterioration of water quality.
Leaves of the Mulberry, Morus sp., are considered among the best shrimp foods, but are also readily taken by plecs. The green leaves are high in protein and have excellent nutritional value. If used properly they will not modify the water parameters.
Walnut, Juglans regia, leaves are famous for their very positive effect on the health of fish and shrimp. They can cure bacterial and fungal diseases and reduce stress just like those of Catappa, but will not lower the pH and colour the water to the same extent.
7 of the best leaves for your tank
All the leaves listed below should be collected in the autumn after they have fallen (naturally) from the trees.
There are several oak species in the UK, ranging from the relatively small-leafed English oak, Quercus robur, to the Turkey oak, Q. cerris, with its palm-sized leaves. They differ in leaf size and shape, but all contain a relatively high level of tannin, which makes them one of the best natural pH reducers. They will also colour the water a medium brown, so they’re not a good choice if you want to keep your water crystal clear. Otherwise the oak leaf is a very easy to find and versatile option.
The Beech, Fagus sylvatica, has quite thin and small leaves, which usually only give a faint yellowish tinge to the water. It will only slightly reduce the pH. Due to its small size, it is very suitable as leaf litter for a nano or shrimp tank containing species requiring a pH that’s close-to-neutral, such as Cherry shrimp, Neocaridina species.
Despite being widely used in urban parks due to its tolerance of air pollution, not many would recognise the Hornbeam, Carpinus betulus. Its small leaves can punch over their weight: the acidifying effect is very similar to that of the Catappa leaf. You might need more Hornbeam leaves to achieve the same effect, but based on weight they can equal their Asian counterpart. They will lower the pH very quickly, so be cautious when using Hornbeam leaves, so as not to stress your livestock. The best way to do it is to drop in a couple of leaves (depending on the size of your tank) every day until you reach the desired effect. It will also give the water a nice brown shade, which is an additional bonus if you want to achieve that black water look.
The Silver birch, Betula pendula, is easily recognisable because of its silver-white bark. It also has small leaves, but won’t alter the pH or the colour of the water. The rigid dry leaves are very slow to decompose, making them an ideal choice if you want to keep your water crystal clear but still use leaf litter for decoration or hiding places.
If you need slightly bigger, but similarly long lasting leaves with only a mild colouring and pH lowering impact then it is worth considering the Hazel, Corylus avellana. It has thick and rigid leaves, which are usually left alone by algae eaters and shrimp, so can serve as a durable decoration.
Sycamore, Acer pseudoplatanus, leaves are one step up in size to Hazel, but have a strong and quick colouring effect. They bleach out quite quickly and the remaining semi-transparent leaf blades will serve as a delicious snail or shrimp food. The pH reducing capability is also short lived, and after the initial sudden drop it will rise again.
The largest leaves of the domestic bunch come from the Plane tree, Platanus x hispanica, which
is another “urban warrior” that’s very tolerant of pollution. It is a perfect choice as leaf litter for
larger fish tanks, as it only has negligible influence on water colour and acidity.
Good for your fish and good for you!
Collecting leaves offers an excellent opportunity to get your partner and/or kids involved in your hobby. Who would resist an offer to visit the nearby country park or forest on a beautiful and sunny autumn day for a healthy walk? My children certainly enjoy collecting fallen leaves — they can fill up my store very quickly.
You can simply drop the required amount of dried leaves into your tank, but if you want them to sink faster you can pour boiling water over the leaves before you add them. This is also useful if you want to reduce water discolouration in your aquarium.
The type of substrate you decide on will have big effect on how much time you’ll need to spend on its maintenance. Our guide will ensure you stay on top of what’s on the bottom.
WORDS: NATHAN HILL
A couple of weeks into owning your set-up, you’re probably looking at the bottom of your layout and thinking ‘that doesn’t look right…’
Different types of substrate need different approaches when it comes to cleaning. If you’ve gone for bleached white sand under a barrage of intense lighting, you’ll probably need to be in there, sifting away daily. If you’ve gone in for a planting substrate, you might never clean it, once.
Here’s how to deal with some of the more readily available substrates out there.
Controversial, but if you have a tank decked out with high-end, high cost planting substrates like ADA Powersand, you either know what you’re doing or you’ve made a big mistake.
Planting substrates are mainly designed to trap and slowly release nutrients to plant roots, and often come pre-loaded with food — that means ammonia. The moment you start trying to rake through them, you release those nutrients into the water column, and that in turn will lead to an outbreak of algae.
How to clean them
- Before going in the tank: Usually you don’t!
- Once in the tank: Some aquascapers suggest removing a section of the substrate every few weeks or months, and cleaning before replacing. Others don’t. My own advice is to run a gravel cleaner about an inch above the surface of any exposed parts, so that you lift any waste without disturbing the substrate itself.
- Heaving with nutrients and perfect for almost all kinds of plant growth.
- Useless for burrowing catfish or excessively dirty tanks.
- Limited choice of colours and grain size.
- Often tends to have a slightly acidic (and rarely alkaline) influence on water chemistry.
Fine natural gravel
Some modern aquarists might be a bit sniffy about this ‘outdated’ substrate, but it still has its place — by which I mean it is a total breeze to clean.
Gravels, and most famously the classic ‘Dorset pea gravel’ became a hobby staple during a time when tanks relied on undergravel filtration. Subsequently they have found themselves on the fringe of fashion, but many tank owners still persevere!
How to clean it
- Before going in the tank: Rinse thoroughly to remove any fine dust. A sieve is fastest, if you blast around 1 or 2kg at a time under a coldwater tap, shaking and swilling like chips in a fryer. Alternatively, place into a bucket and stir continuously while applying running cold water and letting the bucket overflow. Ensure the water is running off clean before draining and adding to the tank.
- Once in the tank: Use a gravel cleaner with syphon to draw water out of the tank and plunge the gravel cleaner deep into the gravel at the same time. The water will lift the gravel, swill and rinse it, then when the gravel cleaner is lifted it will drop back out. A battery or air powered vaccum will do a similar job, but less effectively. You’ll need to do this at least every two weeks, though weekly is considerably better. Monitor how dirty the gravel is each time and adjust as needed.
- The easiest gravel to clean by a mile.
- Inert in freshwater, rarely causes a slight alkaline elevation.
- Looks good in many settings.
- Hides obvious small particles of waste from view.
- Awful rooting medium for most plants.
- Can harm catfish bristles and burrowing species.
- Improper cleaning will lead to nitrate spikes and disease hotbeds.
Silver sand is the choice for numerous biotopes, as it’s similar to substrates found in lakes and rivers the world over. It can be bought in almost any aquatic store, and similar looking substitutes like playpit sand are available where it isn’t.
Despite some detractors claiming potential gut or gill problems associated with using it, it remains one of the most popular modern substrates going.
How to clean it
- Before going in the tank: Slowly, slowly is the key here. Place around 5–8cm depth in a bucket at a time, and stir continuously and vigorously while flushing with cold water. Note, this stage may take a long time, but you need to be thorough as it is hard to remove sand dust once it is in the tank. Don’t try putting it in a sieve as you’ll lose the lot!
- Once in the tank: A gravel cleaner and syphon will just lift the sand out of the tank, though you can use that to your advantage. When particularly dirty, it may pay to remove some sand with a hose this way and rinse it as though going in the tank for the first time — just be careful to limit this to 25% of the total sand, in order not to disrupt filtration. Personally, I like to gently rake my fingers through silver sand on a weekly basis, allowing any muck to lift and drop back down to the surface. Then using a syphon hose, I skim just above the surface of the sand, removing the deposits. This method will result in a fractional loss of sand, which is cheap enough to replace as needed.
- Natural looking.
- Great for catfish whiskers and fish that burrow.
- Almost always inert, doesn’t affect chemistry.
- Many plant roots love it.
- Cannot be used for deep substrates as it can turn anaerobic.
- Can look dirty very quickly.
- Can find its way into filters easily.
- Excitable fish may stir up a tank into a sandstorm.
- Strong filter flows may move it, leaving craters and sand drifts.
Love them, hate them, ignore them, but coloured gravels are often part of the appeal for a new fishkeeper. Not all coloured substrates are the same, either in size, quality or durability, so even cleaning for the first use can be a disappointment.
Before anything, get some of your proposed gravel, put it in a jug with some water, give it a couple of days and test for ammonia. Some coloured gravels are reported to leach ammonia compounds, and if they do, I’d personally bin them — or you can soak them until it goes away.
How to clean them
- Before going in the tank: Rinse gently in a colander or sieve under gently running tapwater. In many cases, some of the colour will run off, leading the aquarist to panic and stop rinsing. You need to keep going until the water runs clear, but do be gentle! The same problem will arise if placing the gravel in a bucket and stirring while gently flushing. Note that some gravels come coated in a resin that will hold in the colour, and for these you can be vigorous, though paradoxically they’ll be amongst the cleanest out of the bag.
- Once in the tank: Gravel cleaners and syphons will need to be used at least weekly to keep coloured gravel clean. The lighter the colour, the quicker algae will start to smother it, and you may find that white gravel only lasts one or two days before needing syphoning again. Be particularly careful with black gravel as it can harbour a lot of solid waste without you noticing, and may turn your tank into a ticking time-bomb of sewage.
- Pretty, if you like that sort of thing.
- Easy enough to clean once in place.
- Some fish will freak out over bright substrates.
- Some types may contain ammonia sources.
- Colours may bleach over time.
- Coarse grains will affect catfish and burrowing fish.
- Can get dirty very fast.
Coral sand has a limited use these days, being restricted to marine set-ups, and hardwater tanks (usually African). It’s actually the product of fish that eat corals, and pass the tiny coral ‘sand’ fragments out in their faeces.
Because it is riddled with calcium carbonate, it will make soft water hard, and subsequently alkaline. Never be inclined to use it in acidic tanks!
How to clean it
- Before going in the tank: Place around 5–7cm of sand in a bucket and flush with cold water while stirring vigorously. Ensure all the sand is turned over as you do this. When the water eventually runs clear, the sand is ready for use.
- Once in the tank: Use a gravel cleaner and syphon weekly or fortnightly and clean as though you would fine gravel (see previous page). In between syphoning sessions, waste from the surface can be removed with a battery powered gravel vacuum, or by wafting a fine net above it and lifting out any waste.
- Acts as a buffer in hardwater tanks.
- Fine enough for some burrowing species such as eels.
- Very attractive in the right setting.
- Intense light will cause algae growth.
- Useless in acidic and softwater tanks.
- Some grades can be very dusty initially, requiring prolonged cleaning.
- Fine particles are sometimes implicated in gill problems in some fish.
Top tips for healthier substrates
Never leave the roots of plants behind when extracting them, as they’ll decompose and churn out nitrates. Rather than pulling plants out, try digging them out.
When cleaning substrates before adding them to your tank, use cold water instead of hot. Some substrates can give the illusion of cloudy run-off water when hot water is used, when in reality they are clean. Microbubbles may be a culprit here
Use nets to remove uneaten food and debris rather than letting it settle on the base.
For marine tanks, lay your sand out thinly on a tray and run over it with a powerful magnet before use. It’s rare, but occasional metal fragments in substrates are not unknown.
The joy of snails! While poorly managed snail populations can become epidemics, having a few Malaysian trumpet snails among the substrate can help turn it over and prevent stagnant patches.
Ponds attract wildlife to the garden and can provide an oasis of life for aquatic organisms, but not all visitors are as welcome as others…
WORDS: JEREMY GAY
We all love wildlife and, unlike an aquarium, a pond can attract visitors that are free to travel to and from the water at will. But which are desirable and which are a downright nuisance?
It all comes down to whether you want a fish pond or a wildlife pond — the two are very different things, and what benefits one may not benefit the other.
If you have fish in your pond they must be your number one welfare priority. Unlike insects, amphibians and birds, they can’t leave and that makes them sitting ducks for all manner of predators. What makes it worse is that we then handicap them with bright colours, fat bodies and a lack of hiding places or distance to escape to.
Here’s the list of regular offenders:
Public enemy number one has got to be the heron. These lanky grey birds will frequent your pond before you get up in the morning, and with no one about, having your pond close to your house is no defence either. Once they’ve found your pond they can more or less empty it of small to medium sized fish, and stab and injure those too large to swallow.
- You can’t harm them as they are protected (although you should never think of doing that anyway).
- Netting can be effective but it would have to be fine, taut and effectively cover all areas.
- Fishing line placed strategically around the pond on stakes can prevent a bird from landing or wading in. Wire can also be placed at pergola height to prevent flying down to the pond.
- Plastic herons are the most commonly practiced defence, although we have heard many stories of owners seeing a live heron feeding next to their plastic one!
- Very visible fish in the pond will be targeted first and are easy to spot from the air. Try mottled Shubunkins instead of bright red goldfish, but failing that, netting is the only way.
I believe that otters have as much right to the waterways as we do, but I can imagine how gutting it would be to find your prize Koi massacred of a morning. Otters are well and truly back, and gorging themselves on ornamental fish all over the UK.
- Netting a pond won’t work, as otters will crawl under it. Instead, you’ll need a wooden frame with no gaps, and a wooden frame with wire mesh on top, with a latch or even a padlock on it.
- Build a waist-high wall or fence around the whole pond, or opt for a raised, formal pond with the frame and mesh top.
Rats are great swimmers, and ponds provide lots of feeding opportunities for them, including eating your fish food. They are a menace though, chewing through pond liners and weeing in the water, spreading Weil’s disease to humans, which at best is flu like but can be much worse. They can predate on other animals, too — I’ve seen them taking baby ducks, so they may have a go at a sluggish fish.
- Don’t leave buckets of pond food poolside, and don’t leave uneaten food on or around the pond. Having bird feeders near the pond may attract them, too.
- Brick-built raised ponds with no exposed liner and no subterranean access to the liner either, solved by a concrete base.
- Small gauge wire mesh.
One of my all time favourite birds, a kingfisher is a wonderful sight. Even the most staunch pondfish breeder surely can’t deny such a handsome and diminutive bird the odd snack, so I say them let them stay and enjoy the moment. They’ll only predate on small, minnow sized fish anyway.
- You are unlikely to have kingfishers if your pond is nowhere near a river or stream — so you could move!
- If you want to say ‘bah humbug’ to ever having a kingfisher visit, or your fry happen to be tategoi or tosakin worth a few hundred quid a pop, simply cover the water with fine netting or a plastic corrugated lid.
Damsel and dragonflies
Only dangerous to your fish when they are fry, damsel and dragonfly larvae are voracious predators which may take tadpoles and baby fish.
- Don’t have any plants and heavily filter the pond. A clinically clean Koi pond with large hungry Koi is unlikely to support any dragonfly larvae, as the fish will eat them.
- Remove all plants and if you are particularly wanting to raise Koi and goldfish fry, very small gauge insect netting will keep the adult insects from laying their eggs in the water. But really, the visual benefit of adults often outweighs the few fry you could lose to their larvae.
These 'sea' birds travel inland the world over in search of food, and can gobble up fish on an industrial scale. If a cormorant lays eyes on your pond and can access it, your fish are in trouble.
- Stop the bird from flying in, perching and diving into the pond.
- High level netting or wire to prevent flight in, and very coarse netting, securely fastened to prevent the birds taking fish. Make sure the net gauge is fine enough to prevent the beak, head or neck from poking through it and grabbing or stabbing fish.
Wild ducks finding your ornamental pond is a wonderful thing for all of about five minutes. They get all excited, wade in and start to dabble and bathe. If you have a waterfall they may play in it — and even climb up and ride back down it! But by the time you’ve rushed to grab that camera, the idyllic scene will have turned into carnage as the ducks start to demolish all your pond plants, uproot the soil in the plant baskets and poo and drop soil into the water, making an instant mess. Your fish will scatter too.
- You need to prevent ducks from both flying in and entering the pond.
- Net the pond high up to prevent ducks flying in, and also at water level to prevent them from wading in. And don’t be tempted to feed the ducks — they will come back.
During heat waves, grass snakes may take to the water to cool down. They can hold their breath and swim underwater, and are reported to occasionally predate pond fish.
- A grass snake won’t wipe out a pond like a heron or otter, and if you have the kind of undergrowth that encourages grass snakes, you’ll probably have frogs and toads too, which the snakes will eat instead. The defence is to prevent access for the snake.
- Why would you want to stop grass snakes from thriving in your garden? Native reptiles are so cool and grass snakes are not in the least bit dangerous. But if you want to stop them, a waist high brick built raised pond will do it. They tend to prefer ground level water with poolside vegetation to retreat to.
In my retail days we regularly fought a very clever crow, which could tell the time and would wait until closing time, before it swept in. Its favourite prey were 5–7.5cm/2–3in Comet goldfish which it would pick from the water, always leaving the head for us in the morning as evidence (herons and cormorants always swallow fish whole, head first).
- You’ll be OK with foot-long fish. Understocking the pond will also not so be as tempting. Feed fish away from the pond edge, as the crow can’t reach very far.
- Net your pond or use a frame and cover, which you can hinge up and down depending on whether you are in the garden or not.
A pretty menacing, quite large aquatic insect, the water scorpion can and does consume large tadpoles, baby newts and pond fish fry.
- The water scorpion will favour sluggish, weedy areas where it can hide and ambush fish, and where smaller fish like to hang out.
- Don’t introduce any plants, stock large fish only, which will eat them, and regularly vacuum your pond walls and base.
I’ve never seen a wild otter, but I saw plenty of mink in the waterways when I was growing up. Mink are indiscriminate pond fish killers and should be treated in the same way as otters. If a mink finds your pond all your fish are in trouble — and chickens if you keep them, too.
- As with the otter, you need to totally block entry to your pond and even small gaps or holes in netting will allow easy entry.
- Brick built raised pond with strong wire on gap proof, lift-proof frame or a strong metal grid.
Movie aliens and monsters have nothing on the octopus when it comes to weirdness. And, so long as you can meet their needs, these animals make intelligent, interactive pets.
WORDS: DAVE WOLFENDEN
Frankly, you’d be hard pressed to make anything up as bizarre as an octopus. They lack a skeleton, but are extremely strong; they suck their liquidised prey through a hole in the middle of their brain; their eight arms are covered in independently-controlled suckers;
they have three hearts, blue blood and can change the colour and texture of their skin.
Octopuses are molluscs, belonging to a group known as the cephalopods (meaning ‘head foot’), making them relatives of squids and cuttlefish. They possess a muscular ‘cloak’ known as a mantle which covers the internal organs, and have a system of jet propulsion thanks to a structure known as the siphon. Rapidly forcing water through the siphon allows for rapid movement. As the shell has been reduced either entirely, or at least is now reduced to vestigial fragments in the mantle, they’re quite vulnerable, so octopuses have developed this ability to evade predators as a defence mechanism. It may be assisted with a puff of ink (which can act as a ‘smoke screen’, or perhaps act as a diversionary tactic to distract a pursuing predator).
To avoid being detected in the first place, these amazing animals adopt cryptic behaviours, and are able to change the colour of their skin via pigment-filled sacs called chromatophores, as well as its texture, thanks to structures known as papillae located across the body.
Octopuses are intelligent, with a natural curiosity to explore any part inside or outside of their aquarium; as a result, they’re interactive, and can assume full pet status.
Octopuses in the aquarium
It is possible to successfully maintain octopuses at home, but they require some key aspects of husbandry if they are to thrive.
Size: Octopuses can vary wildly in size, so it’s difficult to give recommendations as far as tank volumes go, but I’d suggest that the animal needs to have sufficient room to explore, and you’ll need to really judge each specimen on its own merits. If the length of the aquarium is around four times the arm span of the animal, this is a reasonable size.
Filtration and life support: Octopuses are messy feeders with a big appetite, so they generate a lot of solid waste. Therefore, mechanical filtration needs to be able to cope adequately, and the media should be cleaned or replaced frequently. An octopus system will have a relatively high bioload, thanks to the animal’s food, and the ammonia generated by the octopus itself, so efficient biological filtration is essential. Octopuses require optimal oxygen saturation, so ensure adequate turnover. This is important thanks to the relatively inefficient respiratory pigment haemocyanin. They’re not too fussy about nitrate, but aim for zero ammonia and nitrite.
A skimmer will help with ensuring oxygen saturation, as well as pulling out as much waste-laden skimmate as possible. Ozone isn’t tolerated well by cephalopods, so don’t use it.
Water: The quality of the salt water you provide is crucial for keeping octopuses, and they don’t do well in certain budget ‘fish-only’ brands of salt. Use RO water for make-up, and opt for a good, reef-quality salt to be on the safe side. Copper and other metals are a big problem for octopuses, so this is very important to observe. And employ chemical filtration courtesy of activated carbon at all times.
Aquascaping: Most of the octopus species available in the trade are from heterogeneous rocky environments, so replicating this habitat is essential if the animal is to feel secure, exhibit its natural behaviour, and display well. Provide lots of nooks and crannies for the octopus to explore.
Lighting: Your octoquarium should have sufficient lighting to see the animal, of course, but many species won’t tolerate excessively bright illumination. In fact, some octopuses are nocturnal, so you won’t see these until ‘lights out’ generally, although they can adapt to a certain extent.
Enrichment is very important for the long-term health and welfare of octopuses. There are various things which you can do to provide stimulation for the animal. Try randomising feed times, making your octopus work for its food, and simply interacting with it — you don’t have to overdo things, but get creative.
Octo-proof your set-up
As escape artists, octopus would make Houdini blush. As they have no bones or shells to get in the way, they can squeeze their muscular, flexible bodies through the tiniest of holes — it’s as if they can turn themselves into liquid and pour through the gap. And given a chance, they will. Exploration is irresistible to them. Leave them in an open-topped tank, and you’re as good as asking them to leave.
Therefore, a tight-fitting lid is an absolute must. This could be made of glass, or it may incorporate mesh (obviously of the plastic, non-toxic variety), but crucially it must have small enough gaps to prevent escape. This obviously varies according to species or size of individual, but in some cases even a few mm is enough for them to get through. Bear in mind, too, that they’re strong, so any lid needs to be firmly fixed into place to prevent it from being pushed up.
Some public aquariums use wide bands of Astroturf to line the top of their octopus holding tanks to prevent escape — the octopus can’t grip the material properly. However, it’s not really a practical solution for the home system.
Octopuses are extremely curious animals, and it’s vital to ensure that any equipment which could harm them, such as heaters and filter or pump inlets, are well out of reach. Some ingenuity might be necessary to octo-proof any overflows and weirs.
Octopuses are voracious predators, with feeding facilitated by a parrot-like beak and a rasp-like radula, used to macerate their prey; they also possess venom glands used to immobilise the victim. They need to be fed regularly (daily or every other day); provide thawed crustaceans (crabs or prawns) or appropriately-sized fish. Octopuses adapt well to accepting frozen food, and this is preferable. However, they may need to have it presented to them on a feeding stick to get them used to it.
Octopuses generally don’t do well with conspecifics, thanks to cannibalistic and aggressive tendencies, and only a few species can be kept in groups. All the commonly-available species in the hobby should be kept singly. As for housing them with fish — it’s a no-no. Larger species may try and eat the octopus, while the octopus will make short work of smaller species. Many corals and anemones will sting the cephalopod’s sensitive skin, and the octopus will predate upon mobile inverts and clean-up crew. On balance, a dedicated species system is the way to go.
Live fast, die young
Octopuses don’t tend to have long lifespans, which can be an issue. Some small tropical species may live for no longer than six months after hatching, and individuals may be several months old when they make their way into the trade. For a medium-sized species such as the Common octopus, Octopus vulgaris, two years is good going, and with the Giant pacific octopus, Enteroctopus dofleini, which lives in very cold water, you’re looking at just five
years — tops.
A male octopus may suddenly die without apparent warning, but a female will naturally undergo a process known as senescence. She lays eggs (which may be either fertile or infertile depending on whether she has mated), and then spends the rest of her short life tending to them. She’ll refuse food and slowly lose condition, possibly over several weeks.
Senescence can be a distressing phenomenon to watch, but it’s a fact of octopus life — you have been warned.
We don’t know an awful lot about octopus disease. Occasionally, parasites may be a problem, as can bacterial infections of the skin — but these should be left to a specialist vet to diagnose and treat if necessary.
Most health issues are primarily due to environmental factors: for example, ammonia spikes or metal pollution; or through boredom. Therefore, maintaining ideal water quality and a stimulating environment should reduce any potential health problems.
Beautiful — but deadly!
There is a genus of octopuses you’ll want to avoid. Get bitten by one of these, and you’re in for a world of hurt — and they’ve been responsible for deaths. I’m referring to the blue-ringed octopuses (genus Hapalochlaena), of which there are several species.
Blue rings tend to be small (with a span of only 10cm/4in maximum) and beautifully coloured, but they harbour bacteria in their salivary glands which synthesise tetrodotoxin (TTX). TTX is one of the most potent neurotoxins known, and according to survivors, the consequences of a bite sound terrifying, including paralysis.
Amazingly, these animals are imported; they’re not actually illegal to keep under DWA (Dangerous Wild Animals) licensing, but no responsible retailer will sell you one. I know of one dealer who was more than a little concerned when several blue rings were added into a shipment by the collector as a sort of ‘freebie’. Luckily, the dealer donated the animals to public aquariums able to house them.
4 octopus for the aquarium
Octopus offered for sale will often simply be labelled ‘Octopus sp.’ due to the challenges of conclusively identifying them. However, a few crop up frequently which can fairly easily be given an ID. For others, you’ll need a good book such as Mark Norman’s Cephalopods: a World Guide.
Scientific name: Octopus vulgaris (Oct-oh-puss vul-ga-riss).
Origin: Worldwide, across temperate and tropical seas.
Size: At least 60cm/24in span, and perhaps up to 1m/40in.
The Common octopus is frequently offered for sale in the hobby. The situation is a little confusing, as several species from a ‘complex’ are actually sold under these scientific and common names.
Scientific name: Octopus horridus (Oct-oh-puss ho-rid-uss).
The Octopus horridus complex comprises several Indo-Pacific species, and you’ll often encounter these. They tend to have long arms and adopt an extremely cryptic way of life. However, the escape abilities of these octopuses are second to none.
Scientific name: Octopus bimaculoides (Oct-oh-puss bi-mack-you-loy-deez).
Origin: Pacific Ocean.
Size: Up to 50cm/20in span.
Distinguished by the two eye-spot markings, this species is closely related to the larger O. bimaculatus.
Scientific name: Octopus cyanea (Oct-oh-puss sigh-an-ay-ar).
Size: Reaches nearly 1m/40in in span.
Due to its eventual size, this species will require a very large aquarium.
Mbuna are colourful, hardy cichlids that are easy to breed in the aquarium. But they’re also highly territorial fish, so get things wrong and you could have a blood bath. Here’s how to avoid a rocky horror…
WORDS: JEREMY GAY
Fishkeepers the world over struck gold with the introduction of the small colourful rock dwelling cichlids from East Africa’s Lake Malawi. The mbuna as they are known (pronounced mmm-boon-a or mu-boon-a,) are hardy, easy to keep, easy to breed, and widely available.
One qualification any aquarium fish needs to become really popular is colour, and mbuna deliver this in swathes. Yellow and orange are common mbuna colours but importantly, and rarely for any wild-type tropical fish is blue, and this is where the mbuna excel, with literally hundreds of bright blue species, which have tricked many an onlooker into thinking these totally freshwater fish are in fact marine.
Next is the number of species you can keep together. No other aquarium is capable of holding as many different species of fish per volume as a Malawi cichlid tank. An average mbuna community could hold 30 different species — a large tank 50 or more. You wouldn’t be able to keep 30 Central American species in one tank — it would be chaos — and even a community tank of fish from many different, very varied genera would struggle to hold that many because so many species need to be kept in groups of their own kind. This all adds to the overall appeal of mbuna.
Mbuna in nature
To keep mbuna at their best we must first look at how and where they live in nature. Mbuna are endemic to Lake Malawi in Africa’s Great Rift Valley — a 3,700-mile long trench created by the African tectonic plate tearing apart. Malawi is a gigantic crevice. It filled with river water and fish — and these then changed, evolved and adapted to suit their new, lacustrine environment.
And it’s big. Malawi is the ninth largest lake in the world and the second deepest, at 706m. Its 360 miles long, 50 miles wide and some 11,000 square miles in area. That’s bigger than Wales…
A lake of that size comes complete with waves, rocky cliffs and sandy beaches. Tales abound of early explorers mistaking it for an ocean, which let’s face it, you would.
Cichlids entered Malawi via its tributaries, with two tribes — the tilapiines and the haplochromines — taking up permanent residence there. Things got interesting for the haplochromines however, which went through “adaptive radiation” and today comprise around 1,000 species, which is about as many as live in the whole of the North Atlantic! This was great news for human populations who could then fish the lake for food, scientists who could study evolution — and us fishkeepers, who get to marvel over Malawi’s bountiful beauty in our home aquariums.
So think freshwater reef fish and you would be about right, as the colourful yellow and blue mbuna we keep bask in the clear blue, sunlit waters and live in and around the rocky outcrops. Cichlid paradise!
But the fascination doesn’t stop there, as the mbuna deliver a double whammy of appeal by way of how they breed. All the mbuna, and all the other haplochromines in Lake Malawi are maternal mouthbrooders, meaning that they lay eggs, which are then taken into the female’s mouth where they are incubated, hatched, and then finally spat out as fully formed fry.
This paid dividends for the early cichlid colonisers of the lake bed as even breeding females were not tied down to any one small patch for a month at a time and instead could be upwardly mobile, go forth and colonise. The uninitiated wouldn’t know that a female was with eggs or fry at all, and the males didn’t have to turn into giants who would then have to defend the fry against all comers, whether fish, bird or reptile.
Keep mature males and females together in the home aquarium and they will breed. And for many mbuna keepers the progeny can provide a useful supplemental revenue stream.
Keeping them at home
The good news about mbuna is that although there are so many species, they can all be kept in exactly the same way, eat exactly the same food, and once you have conquered keeping them for the first time you can pretty much keep any of them, as long as you observe the fundamentals.
Coming from such a large lake, the mbuna are used to clean, clear water, which is free of pollutants and rich in oxygen. In the aquarium this means they need lots of mechanical and biological filtration, plenty of water changes to keep nitrate at low levels and extra aeration by way of an airstone or Venturi outlet on a filter.
Next is the chemistry of the water. All that tectonic plate activity under the lake has meant that Malawi is very rich in minerals, which give it a high pH, KH (carbonate hardness,) and GH (general hardness). Those with scaled-up kettles and hard tapwater will do really well with mbuna — these aren’t fish for soft, acidic water conditions. So it’s no to reverse osmosis water without adequate amounts of Malawi cichlid salts first being added, and decor should include calcareous, lime-based decor or filter media to keep those minerals high and pH, KH and GH buffered.
In the wild mbuna rarely top 7.5–10cm/3–4in total length but fed rich foods in the aquarium they can reach 12.5–15cm/5–6in. They are aggressive and territorial and you need to keep lots of them, so a large tank is a must.
To start right with mbuna a 120cm/4ft tank or larger is best. Yes, breeders and the shops keep them in much smaller set-ups but this ability comes with experience, and it’s far from ideal. Some species are classed more as dwarf mbuna, and these might do well in a tank of 90–100cm/36–40in, but even then a taller, wider tank with a volume upwards of 180 l/40 gal is best.
When creating a home for mbuna, try to replicate the lake environment — deep and wide. A 120 x 60 x 60cm/48 x 24 x 24in tank will be much more conducive to the lake effect than a 120 x 30 x 30cm/48 x 12 x 12in aquarium, which holds far less water and is much better suited to replicating a small, shallow stream.
Getting started with mbuna can be somewhat of a trap for the uninitiated, as many of the most widely available species are the least suitable for the novice.
Melanochromis auratus is probably the most widely available, with juveniles displaying attractive humbug patterning. It must be said that this is a very hardy, durable species — but it is also one of the most aggressive and will quickly dominate, then terrorise a new, sparsely populated tank. Males and females become duller and more dirtier-marked too, losing much of the bright striping.
A first foray into blue fish can also be folly, with Pseudotropheus socolofi being an attractive powder blue colour, but becoming aggressive and quite large with age, while Metriaclima lombardoi starts life with blue vertical banding on both sexes, the males developing a lovely bronzy yellow as they mature — along with a foul temper! Add a few unidentified hybrids and you can soon end up with an aggressive, nasty set-up, which is anything but relaxing to watch.
Seek out a cichlid specialist who will have more species and better labelling. There you will be able to buy bright yellow but mild-tempered Labidochromis caeruleus and dark blue but small in size and temper, Melanochromis cyaneorhabdos. You can also add a group of lilac-coloured Pseudotropheus acei — the least mbuna-like mbuna of all, being generally placid. Tropheops are underrated, subtly coloured and generally well behaved mbuna, which inhabit the shallows and graze algae. Some are quite collectable and any shop holding several species such as T. chilumba, macropthalmus, microstoma and sp. ‘red cheek’ are definitely worth their cichlid salt.
And if you want to break up the bright blues and yellows, how about a bit of brown? Look out for the subtle beauty of Pseudotropheus elongatus ‘chailosi’ or Cynotilapia sp. ‘Lion’.
Large aggressive species
These fish are best avoided by the novice mbuna keeper:
Smaller, less aggressive species
Try these instead:
Male and female mbuna don’t form mated pairs, and that does mean that male mbuna can be troublesome. To put it simply, every male mbuna wants nothing more than to be the only male haplochromine in the whole of Lake Malawi — or better still, the whole of the world.
Males want to adorn themselves in the brightest colours and live over the best real estate, and their idea of heaven is to be visited every ten minutes of every day by a female looking for a casual fling and who then disappears, never to be seen again!
Hell for a male mbuna is to be surrounded by other males — other better looking, more masculine males — who then eat their food, take up residence in their space and worst of all, take all their women. This results in a typical male response — fighting — and females who don’t know when to leave will get battered, too. If you’re 7.5cm/3in long and aquatic, never get within a few metres of a male mbuna with a rage on. It will hurt!
But of course the problem here is that most of our tanks are only a metre long — maybe a metre and half at best — so with what we now know about mbuna psychology, we can see that we have an anger management problem that needs to be addressed. Rival males and non-sexual females will always be in the vicinity of dominant, sexually charged males, so it’s how we deal with it which will make or break your mbuna “community”.
The first thing to consider is decor. In Malawi the rocks where mbuna are found would need moving with a JCB, but we can use lots of smaller rocks, say 15cm/6in across, in piles in the aquarium. A rock gives a male something to call his own, somewhere to feed and breed — and if you use limestone rock it will even buffer your water and help to make it hard.
Pile the rocks together and females, fry and subdominant males can take shelter in the crevices and get out of the line of sight of the aggressive male. He won’t attack them if he doesn’t know they are there.
Next, pile rocks high to further obscure the line of sight across the aquarium. Make a visual barrier and two males will separate and coexist, each defending his own tiny territory. Add lots and lots of rocks and you can keep even more males in this way.
The next line of defence is to overstock. You have lots of filtration and lots of aeration, so go wild (filter bacteria levels permitting), and quickly build up a high number of similarly sized, similarly aged (ideally young, sub 5cm/2in fish). Twenty individuals should be seen as an absolute minimum, but 30 or 40 is even better. Grow them up in a crowded situation where they all know one other and anger can be managed. Outnumber a male of each species by at least two females, so that one poor female doesn’t get singled out and harassed. Or don’t have any females at all — but you’ll miss out on the joys of breeding.
Like a cockerel with a group of hens, the one thing that’s really going to wind up your male is another male of his own size and kind. He’ll fight to the death to protect what is his, so a newly introduced, disorientated male will always come off worst. Passing on one’s bloodline overpowers every other emotion or driver in nature.
Overstock and the aggressive male can’t spend too long away from his rock chasing other fish, as another fish could take up residence while he is away (or so he thinks). And that’s how Malawi mbuna tanks work.
Feed with care
In nature, mbuna feed on aufwuchs (a German word, meaning surface growth). This growth on the rocks consists of short strands of algae, biofilms and the tiny critters living within it. At certain times of year mbuna will also graze on zooplankton blooms higher up in the water, and massive scale midge hatches which rise up hundreds of metres above the lake like huge plumes of smoke as they hatch and mate.
For the Malawi cichlid geeks it’s the subtle specialisation of the 1,000 species when times are tough and food lean, which is so fascinating. Like zebra and wildebeest on the savannah, which coexist by each eating different lengths of grasses, the mbuna do so by eating different lengths of aufwuchs, and grazing it in different ways. The underslung mouths of the Labeotropheus allow those fish to access and rip off the best algae growths in choppy water with very little levering, keeping their bodies flat against the rocks as they do so. But the more insectivorous Labidochromis have to turn their bodies head first, at 90° to a flat surface, and then expend more energy ripping at the algae.
So, in the lean times, each species uses its specialisation, be it for eating short algae, long algae, invertebrates, insect larvae, eggs, scales or even fry — that’s why there are so many different species in Lake Malawi rather than millions of individuals of just one or two species.
In the aquarium, these specialisations are virtually never called upon, so mbuna grow big and fat on rich diets and regular feeds. This gives rise to so-called “Malawi bloat”, although many other underlying factors probably also contribute to the disease. In a mbuna with bloat, the neck and stomach become swollen and firm to the touch; the eyes pop slightly. It’s almost always fatal.
Popular advice is to avoid rich foods aimed at South American carnivorous cichlids and instead offer mbuna specific diets, which contain lots of algae, vegetable matter, and low animal protein. Frozen bloodworm is also attributed to causing bloat, although it is actually very low in protein and instead high in chitin, and mostly water.
Leave off feeding for one day a week and your mbuna will take to the rocks, cleaning up algae and clearing out their systems.
8 essentials for success with mbuna
- Hard, alkaline water — pH upwards of 7.5; temperature 24–26°C/75–79°F.
- Well-filtered water — zero ammonia and nitrite; nitrate should be below 40ppm.
- Well-oxygenated water — add extra aeration with an airstone or Venturi.
- A large tank — 180 l/40 gal minimum, but ideally 240 l/53 gal or more.
- Lime based decor — to aid pH buffering.
- Rocks — provide lots of them to offer territories and hiding places.
- Overcrowding — 20-plus fish in every community.
- The right food — offer an algae-based diet aimed at herbivores.
Don’t let them hybridise!
Mbuna will hybridise in the aquarium, and for the sake of other mbuna buyers, this should not be encouraged. Don’t keep females without a male of their own species in the community and if fry are suspected to be of hybrid origin, don’t spread them in the hobby. Although exciting to some, a new species won’t be created in this way. Instead, that world record breaking cichlid diversity will be watered down and diminished — and those unique colours, patterns and specialisations will disappear.
Any tank you ever set up will be subject to an algae outbreak sometime. The trick is to learn to manage, rather than completely eradicate it.
WORDS: NATHAN HILL
Every newcomer to the hobby will be united in asking, somewhere around three or four weeks into their experience, about how to deal with the algae forming in their tanks.
It’s no coincidence that some tanks are hit harder with the green stuff than others. Algae are numerous in their forms, from microscopic green ‘orbs’ that drift like balloons, to long, pernicious strands of red or black that carry the resilience of a born survivor.
The basic algae problem involves a tank full of water, light (which supports plant life), nutrients (either too much or too little) and carbon dioxide (which may or may not be in your control.) Wherever these ingredients are found, they present an opportunity for algae to grow.
For the everyday aquarist, there are a few strains that might appear, and there are different ways to deal with each one. Algae is not algae, is not algae. There are the green
and red varieties, needing different handling approaches, plus the peril of ‘algae’ that isn’t even true algae.
It’s important to diagnose and understand what type you’re up against before you decide on what action to take against it.
This is quite a rarity in tanks (as opposed to ponds) unless you’re tampering with carbon dioxide and nutrient levels, but it can still strike out of the blue.
The cause is a unicellular alga that lives free in the water, too small to get trapped in filters, and too persistent to be diluted out with a simple water change or two.
Ammonia is implicated in causing and sustaining green water, and stirring up substrates, subsequently releasing ammonia in to the water, can be a trigger. Off the shelf algaecides may help, water changes do very little, and my own experiences have found that a temporary black out where lights are turned off and the tank shrouded to keep out any external light will help reduce it, but not always eradicate it.
To add to the frustration, it will often disappear in a day or two entirely on its own.
Green dust algae
An alga type that’s found mainly in new set-ups, green dust lives up to its name. It mainly forms on the glass and hard, smooth decoration like rounded stones, and
given time to cement itself in place it can be stubborn.
Attacking it frequently seems to make it linger, and aquascapers will sometimes just leave it alone for several weeks (until the glass becomes near impossible to see through) before removing en-masse by scraping it from the glass with a blade or plastic edged cleaner, and then syphoning out the removed algae from the base.
Oddly, in heavily planted tanks, a low level of nutrients can be part of the cause, but unless you’re a dedicated aquascaper you won’t want to add more plant food!
Blue green algae/cyano
If you suffer from this, then I feel for you. Blue green algae isn’t algae in the true sense, but is a type of bacteria that can photosynthesise. It will quickly drape all that it can in a tank with thin, expansive sheets that often peel away in large pieces. Controlling it is nightmarish, and short of using antibiotics (which are illegal without prescription in the UK) you’ve a long fight on your hands.
In a home tank, the cause is usually a combination of direct sunlight hitting the glass, combined with dirty substrates that harbour rich beds of organic matter. Ammonia can trigger it, and a new tank is likelier to get it than an old one.
To start controlling it, you need to physically remove as much as you can via net and syphon. At the same time, you need to work on substrates to get them scrupulously clean, as any muck down there will entice it to return.
To eradicate it, you’ll need a complete tank blackout for around four days, so turn off all lights and wrap the tank in something dark so that light can’t get in. It’s noted that increasing oxygen levels can also help out, so get an airstone in the tank too.
This is the most common alga you’ll meet, and it’s formed of tiny diatoms. If you’ve set up a new tank, it’s the first alga that will appear, and is associated almost entirely with the silicates and ammonia that goes hand in hand with an unestablished system.
Brown algae will vanish within a few weeks of setting up. If it doesn’t, that algae isn’t the problem, but rather something is stifling the maturing process of the tank. It may be an issue with the filter, or it may even be excess movement of the substrate. Stirring the base up too often can cause it to linger, but only when the tank is new.
Dealing with it is as easy as getting in the tank with an algae pad, wiping it from the glass or other hard surfaces, and then syphoning out what drops to the base of
Though some fish (like Otocinclus) will eat it, the paradox is that brown algae will almost always indicate a tank too immature to keep them. Clean and wait, and eventually the algae will go.
Green spot algae
Not to be confused with green dust algae, green spot is more tenacious and stubborn, with larger individual blobs.
In aquascapes, it tends to be associated with low CO2 and low nutrient levels, where in most domestic community tanks it tends to be a consequence of excessive lighting and poor water flow. Bright, near-static tanks are almost always problematic.
To clean from glass, hard scrubbing with a pad or magnetic cleaner will keep it in check, though a razor or plastic edge may be needed to remove it once it gets a foothold.
Green spot algae on decoration will require scrubbing with a toothbrush. Remove affected decor and brush it under running water.
Leaves showing coverage of spots are best removed using sharp scissors.
Performing a series of small water changes (10% daily for five days) may help to reduce some of the available nutrients. Cut back on the amount of light during the day — anything over eight hours is inviting green spot.
Black brush algae
‘Black’ algae is misleading, as this is actually classed as red algae. In the tank, it tends to be more of a sooty grey, but its presence is unmistakeable. Small, beardlike tufts of dark, fluffy algae will jut from all surfaces, ornaments and plants in a slow encroachment, until eventually the whole tank is smothered.
It’s associated with a few factors in community tanks. High phosphates are implicated, as is inadequate flow of water. Old light tubes in particular seem to promote its growth, and fluorescents over 12 months of age should be replaced to prevent it.
It can often be found living directly on wood, feeding on leeching organics.
Controlling it is nightmarish. Any plants that show signs of infestation should have the affected leaves sacrificed immediately. Any growths on glass should be scraped away with blades or plastic edges, and the tank syphoned to removed the fragments immediately after.
Decor that is smothered can be treated by removing it from the tank and soaking it for five minutes in a mixture of glutaraldehyde (such as Easycarbo, or Flourish excel) at a ratio of 25% treatment to 75% water. After soaking, rinse thoroughly before returning to the tank. Dosing Easycarbo to the tank will help to control brush algae in the long term, as it’s toxic to the algae but not to higher plants.
Water changes will help in some cases, while less water changing helps in others, as will certain fish and shrimps. Try redirecting filter outlets to provide more flow around the tank, or even consider an additional small pump or powerhead to increase movement.
Looking similar to black brush algae when small, staghorn forms long, antler-like tangles. It tends to prefer plants over substrates or decor, smothering leaves with its growth.
Dirty tanks with sediment trapped in the substrate are desired real estate for staghorn, and toss in slow water flow and ageing lights, and you’ve a perfect recipe for growth.
Cleaning the substrate, removing affected leaves, and treating with glutaraldehyde will all help, as will improved flow rates.
Fish and inverts: Some fish will consume algae as part of their natural diet. In fact, many species have long been marketed as remedies to outbreaks. Here are some of the classics...
Far from cheap, not always readily available and sometimes difficult to keep, aquarists just love those suckermouthed plecos. Here are some of the species that breeders and collectors adore.
WORDS: NATHAN HILL
1. Zebra plec
Scientific name: Hypancistrus zebra (High-pan-sis-truss zeb-ra).
Origin: Endemic to the Rio Xingu, Brazil.
Size: To 8cm/3.1in.
Tank size: Minimum 60 x 30cm/24 x 12in.
Water chemistry: Soft acidic to slightly base water; pH 6.0–7.5, hardness 2–16°H.
Feeding: Carnivorous fish that enjoys bloodworms, brine shrimp and even Daphnia.
Notes: Despite being threatened by dam construction, wild caught fish offered in the UK may well have been illegally caught and smuggled out via other countries. Tank bred/farmed fish are available and completely legal.
2. Gold nugget plec
Scientific name: Baryancistrus xanthellus (Barry-an-sis-truss zan-thel-us).
Origin: Rio Xingu and Iriri, Brazil.
Size: To 22cm/8.6in.
Tank size: Minimum 120 x 45cm/48 x 18in.
Water chemistry: Slightly acidic to slightly base; pH 6.4–7.6, hardness 2–14°H.
Feeding: Omnivore eating some algae and inverts. Offer Repashy gel foods.
Notes: Territorial with other cats, aggressive with other nuggets. Will leave plants alone in a planted layout.
3. Sunshine plec
Scientific name: Scobinancistrus aureatus (Scoh-bin-an-sis-truss or-ee-ate-us).
Origin: Rio Xingu, Brazil.
Size: To 30cm/12in.
Tank size: 180 x 60cm/60 x 24in.
Water chemistry: Soft acidic to neutral water; pH 5.8–7.2, hardness 2–14°H.
Feeding: Omnivore, offer prawns, mussels and fish pieces, as well as fruit and veg with the skin on.
Notes: Big and robust, and retains gorgeous markings into adulthood. Excellent in a tank with other large fish such as South American cichlids.
4. Blue phantom plec
Scientific name: Hemiancistrus sp. L128 (Hem-ee-an-sis-truss).
Origin: Rio Orinoco, Venezuela.
Size: To 18cm/7.1in.
Tank size: 120 x 30cm/48 x 12in.
Water chemistry: Soft acidic to neutral water; pH 6.0–7.0, hardness 2–12°H.
Feeding: Omnivore, offer tablets, gel foods, vegetables and frozen bloodworm.
Notes: Works surprisingly well in a peaceful, slightly acidic community tank, though can take a while to acclimate to a new set-up.
5. Royal plec
Scientific name: Panaque nigrolineatus (Pan-ak-ay nig-row-lin-ee-ah-tuss).
Origin: Colombia, Venezuela, South Central Amazon Basin.
Size: To 35cm/13.8in.
Tank size: 180 x 60cm/60 x 24in.
Water chemistry: Slightly acidic to slightly alkaline; pH 6.5–7.5, hardness 4–15°H.
Feeding: Veg, veg and more veg. Offer greens, peas, and fruit. Ensure there’s wood in the tank for them to graze on.
Notes: There are many varieties with subtle differences between them. Whichever one you get, expect someone to dispute its identity.
6. Flash plec
Scientific name: Panaqolus albivermis (Pan-ak-ay al-bee-verm-iss).
Origin: Rio Alejandro, Peru.
Tank size: 90 x 30cm/36 x 12in.
Water chemistry: Acidic to alkaline water; pH 6.6–8.4, hardness 4–18°H.
Feeding: Xylivore (wood eater), ensure wood is always present in tanks, along with offered vegetable fare.
Notes: Frequently misfed, these plecs go very well in a set-up with South American tetra, but they can become more territorial as they mature.
7. Colombian blue-eyed plec
Scientific name: Panaque cf. cochliodon (Pan-ak-ay cok-lee-oh-don).
Origin: Magdalena and Cauca basins, Colombia.
Tank size: 180 x 60cm/60 x 24in.
Water chemistry: Soft, acidic to neutral water; pH 6.0–7.4, 4–14°H.
Feeding: Xylivore (wood eater), ensure wood is always present in tanks, along with offered vegetable fare and occasional meaty treats like prawn.
Notes: Rarer than an uncooked steak, if you find one in the UK you’ll be one of a small handful
of people to ever see these fish in the flesh.
8. King tiger plec
Scientific name: Hypancistrus sp. L066 (High-pan-sis-truss).
Origin: Xingu, Brazil.
Tank size: 90 x 30cm/36 x 12in.
Water chemistry: Very soft acidic to neutral water; pH 5.8–6.9, hardness 2-8°H.
Feeding: Carnivorous, offer plenty of bloodworm and prawn, as well as carnivore tablets and pellets.
Notes: Prone to being confused with other species, you get a very pleasant fish for not too absurd a price. A real keeper.
9. Magnum plec
Scientific name: Baryancistrus chrysolomus (Barry-an-sis-truss cry-so-low-muss).
Origin: Rio Xingu, Brazil.
Tank size: 120 x 45cm/48 x 18in.
Water chemistry: Slightly acidic to slightly alkaline; pH 6.5–7.5, hardness 4–15°H.
Feeding: Omnivore, ensure algae growth but add veg like courgette and sweet potato.
Notes: Juveniles tend to be more contrasted than the adults.
If you’re tempted by killies but not sure which species to start with, you won’t go far wrong with Aphyosemion striatum, says Steve Davidson.
Common name: Red striped killifish, Striatum killifish
Scientific name: Aphyosemion striatum (Aff-e-o-see-me-on stry-ar-tum).
Lifespan: Around two years.
Ease of keeping: No problem for competent fishkeepers and a perfect introduction to killifish.
Feeding: Will accept some flake food, although as with all killifish they much prefer live foods. Frozen mini bloodworm is taken with relish.
Availability and cost: Sometimes found in shops, on internet auction sites, and certainly through members of the British Killifish Association. Price around £12–16 a pair in shops, but less if bought from a dedicated hobbyist/breeder.
Every so often we come across a fish that stops us in our tracks. Perhaps it’s the shape of the fins — or, as with the Striatum killifish, it’s the colour.
This stunning tooth-carp has colours that would rival the brightest marine fish, with shades of red, green, yellow and blue all packed into a slender body that is just 5–6cm/2–2.2in long. The colours are clearly defined, and similar to the vibrant punchy shades often found in a children’s playground. An added bonus with this little beauty is the ease with which it can be kept
Aphyosemion striatum is native to Africa, found in Gabon and Equatorial Guinea. It inhabits mainly small streams and swampy areas within or bordering the rainforest and has been found in water that is quite shallow. When collectors have been looking for small Aphyosemion species in the rainforest, many have reported finding fish close to the bank. Where trees overhang this creates some shade and here the water temperature will be slightly lower — often around 20–23°C/68–73°F. Aphyosemion striatum falls within this temperature range.
In the aquarium
This is the ideal species for the newcomer to killifish. It’s not too hard to obtain and is easy to feed as well as making a great breeding project — and then there’s all that colour!
You don’t need a large aquarium to keep these fish — a pair or a trio (one male, two females) can be housed in a 30 x 20 x 20cm/12 x 8 x 8in tank. Ensure you have a tight fitting lid as many killifish are aquatic gymnasts, and may launch themselves out of the water and through a tiny gap. The water needs to fill around 70% of the tank and be around 23°C/73°F in temperature — a couple of degrees either side of this can have an effect on spawning activity.
For many years I used mains water with the obligatory water treatment to render it safe for my fish, but a couple of years ago I switched to using 100% rainwater for my killifish and guppies. It has a pretty consistent pH of 7 but anywhere between the range of pH 6.6–7.2 should be fine for these fish. In the past it was common practice to use some pre-soaked Irish moss peat as a substrate for killifish, but if your water is pH 7 or below the peat could make your water too acid over time. Nowadays many killie keepers use pre-soaked coir as it is considered inert, so should not alter your water chemistry. An airline bubbling away quietly and a spawning mop or two made of a synthetic wool is all that is required. You don’t need real plants although they do enhance the appearance of the tank.
Some killifish species can be a bit reluctant when it comes to spawning, but A. striatum is a species that should present few (if any) problems for a reasonably competent aquarist.
Storing the eggs
The eggs of these fish are fairly small, but when the adults are conditioned well they will be laid in profusion. There is always some debate among killifish-keepers as to the best way to store eggs. Some people say to put them in a small container, such as a well cleaned 500g margarine tub containing some of the parents’ tank water. Others, like myself, favour putting them on a small amount of damp peat in a small container with a lid. I use small plastic containers around 45mm in diameter with a lid attached by a small integral strap. I cut up computer address labels for attaching to the egg containers. These can then be used to record the species name, date collected, and number of eggs.
The eggs take on average 16 days or so to hatch. I hatch eggs in small plastic containers made from a clear Tupperware type plastic, around 100 x 50 x 75mm (sold for craft purposes in stores such as The Range).
Rearing the fry
Fry are quite small on hatching and ideally should be fed newly hatched brine shrimp which is full of protein. A word of caution though, feed brine shrimp very sparingly. Any that is not eaten will die fairly quickly and foul the water. If this happens it’s very likely the fry will succumb to velvet. In my experience once this occurs with fry it’s fairly certain you will lose them, so exercise caution when feeding fry! Microworms that are kept in a Ready Brek type mixture can also be fed to the fry. A singular use of a child’s paintbrush is ideal for feeding these — just dip the brush into the worms so a few of them attach to the tip of the bristles and then swirl it in the tank.
With fry held in small containers you can monitor their progress. The relatively small amount of water will slowly evaporate within a fish room, so topping it up with similar water is required. I tend to decant off around 50% of the water into a cleaned out margarine tub, allowing me to see any small fry that have carried over. If you do not have the luxury of a space heated and dedicated fish room then you will need to find a way of keeping the fry container warm —floating it in the parents’ tank is an option, providing it won’t topple over.
Growth will be slow as is the case for most Aphyosemion species. As soon as they reach around 8mm long I transfer them to a small tank somewhere in the region of 20 x 10 x 10cm/8 x 4 x 4in. This gives them more room to develop. I still change around 40–50% of the water at least once a week to keep things sweet. Changing a portion of the water also helps to maintain an even growth rate among the fry. If you can arrange for a very slow trickle of air via an airline and valve/clamp then this will prevent the water from skinning over. If this is not feasible then gently moving the water around with a clean finger will do the trick.
When fry reach 12-15mm in length you can consider moving them on to something like a 30 x 20 x 20cm/12 x 8 x 8in tank. This is big enough for them to grow on but still small enough to be able to monitor the fry. You should be able to spot any uneaten food in a tank of this size and remove it before problems unfold. Continue with feeding freshly hatched brine shrimp which can be supplemented with some very small Grindal worms as the fry grow.
You can of course leave the eggs to hatch within the parents’ tank. The plus is that fry hatching in tanks alongside their parents seem to grow a bit faster than when hatching and rearing them separately. But some fish will devour their fry, and larger fry will sometimes consume newly hatched individuals, although just today I have found some fry a few weeks old swimming happily alongside their parents.
After a few months you should end up with some fish whose colours approach or even rival that of marine fish.
Join the club!
Become a member of the British Killifish Association. Find out more at www.bka.webeden.co.uk
Older aquariums can have issues of their own, leading to dead fish and terrible water. The tragedy is that it’s so simple to avoid this kind of problem, says Nathan Hill.
If you’ve kept fish for anything more than a couple of days, then you’ll be either directly or indirectly intimate with the problem of new tank syndrome, often abbreviated to NTS.
I won’t dwell. We should all know the basics of new tank syndrome, though discussion about the exact mechanisms is heated. Fish make waste, the filter struggles to cope with that waste, and contingency plans need to be in place. You might prefer ex-situ tank maturation or in-situ. These are arguments for another time.
Unfortunately for many fish, too many aquarists assume that new tank syndrome is the only water worry they’ll ever face. They imagine that this initial establishment period is the only time they’ll struggle with instability.
Because of this, they may be caught out by an equally dangerous, yet easily avoidable problem later down the line: old tank syndrome, or OTS.
In old tank syndrome, the definition of 'old' is open to some discussion. Tanks that have been running successfully for months or years may slowly turn bad, or they might suddenly crash altogether, with multiple casualties and a befuddled owner.
The problem all too frequently lingers unseen, and then manifests itself in a way that leads to conflict between fishkeeper and retailer.
Imagine the scene, if you will. A fishkeeper has a tank that they’ve kept successfully for two years. In that time, some fish have grown, while others — conceivably through old age — have died. The plants are large, maybe a little leggy, but still alive, and overall there is no reason to suspect any underlying malaise.
This fishkeeper opts to buy some more fish from a local store, deciding to pick up some delicate tetra types, given how 'mature' their tank is. A day or two after adding the fish, problems are noted. They look bedraggled, and show the first signs of whitespot. Not long after, the tank is knee deep in a full scale Ichthyopthirius pandemic, with old and new fish dying everywhere.
The immediate impression of the fishkeeper is that they have been sold diseased fish, and so they return to the store to confront the retailer and demand replacements — only to discover that every one of the original tetras still in store is the absolute picture of health.
As is their right, the retailer requests a sample of the fishkeeper’s aquarium water before a resolution can be made, and that sample, when it arrives, turns out to be diabolical beyond compare. So bad, in fact, that even without the new fish, the tank would have been weeks away from a wipeout anyway.
And that is how most people meet old tank syndrome.
More to water than filters
If I was going for an easy sale in a store, and I had to describe a filter’s function as simply as possible, then I might be inclined to say that 'it takes all the toxic waste and makes it safe for the fish to live with'. I suspect that for a lot of casual fishkeepers, that’s the impression they have in mind. Fish make waste, filter resolves waste, problem solved.
If only it was that that simple.
Filters only convert waste, and certainly not into something safe. Ammonia from fish is converted through nitrite and into nitrate. That much we all know, right? Water chemistry 101 right here.
Nitrate isn’t exactly a 'nice' chemical to have around. In humans, it’s implicated as a carcinogenic, while the lethal levels for different fish are slowly being understood.
As long as the filter is working, and as long as the fish are producing waste, then there will be nitrate produced.
It would be wrong to say that some fish develop a tolerance for nitrate, because that implies that they can be unharmed by it. Rather, I consider long-term nitrate exposure in fish as analogous to alcoholism in humans. It slowly affects organs, reduces lifespans, and plays havoc with immune systems. To be in optimal health, they need to live lives devoid of it. Like drink in humans, a little bit of it might not be a major problem. A lot of it is.
The problem is that aside some slight loss of condition, maybe dull colours or lethargic behaviour, there’s little to see that suggests a fish is suffering in high nitrate levels.
Even worse, if a fish is then taken from water where there is very little nitrate (such as in the case of my hypothetical retailer earlier) and suddenly exposed to high nitrate, then it is likely to shock it. To stay with the drinking analogy, someone unhealthy but used to drinking heavily would cope better with a ten pint boozing session than a person in perfect health who has been a lifelong teetotaller. Think Rab C. Nesbitt versus a nun. It’s a crude way to explain it, but that’s pretty much what happens.
There’s also phosphate to consider. Phosphate is introduced courtesy of the foods we offer our fish. It is not metabolised to any degree, and ends up excreted as waste.
Phosphate has questionable health impacts on fish, and is much better understood to inhibit invertebrates. Marine keepers in particular struggle to control it. As phosphate builds, the most obvious symptom is increased algae growth. In waterways, excess phosphate leads to eutrophication (it is the prime cause of eutrophication), which turns rivers and lakes bright green with algae, stripping the water of oxygen and killing the inhabitants. Such pandemics are not well known in aquaria, though that’s not to say they never happen.
Again, all of this is very easy to avoid.
The acid effect
The worst culprits for OTS are tanks that become victims of their own success.
An underlying problem involves the hardness — the mineral content — of the water. Carbonates play a vital role in buffering aquarium pH, as well as providing a source of carbon for some plants and bacteria: specifically those bacteria helping to convert fish waste.
When carbonates become depleted, two problems follow. Firstly, the osmoregulation of many fish (the way in which they regulate their minerals in the body) is compromised, sometimes to lethal extents. Secondly, without the buffering effect of minerals to keep it in place, pH in the tank can drop or swing wildly, leading to acute acidosis. Either of these can kill a fish outright, and both will cause acute and chronic stress.
Bacterial action inside the filter further alters pH. Biological bacteria, as they work, produce quantities of hydrogen ions. In water, these take the form of hydronium, and the amount of hydronium relative to the amount of hydroxide dictates how acidic the tank is. The more hydronium, the lower the pH, and with a busy filter churning the stuff out, pH levels can soon plummet. Combine that with the simultaneous removal of buffering carbonates as already mentioned, and you have a pH disaster in the waiting.
To make things even worse, if the pH does drop too far then it will stop the filter from working properly. In acidic conditions, the bacteria that convert ammonia struggle to function, and below 6.0pH they might stop working altogether.
Prevention trumps cure
Every parameter mentioned here can be tested, inexpensively and easily. Liquid kits, dip strips, monitoring devices — there is no excuse. Folks who say they can visually assess their tanks are deluding themselves, at the peril of their fish. You cannot ‘see’ the nitrate content of a tank any more than I can 'see' the alcohol content of a glass of gin.
Over the years, there has been something of a misunderstanding. Many aquarists are only keen to test — or in some cases have their retailer test for them — while they are cycling the filter at the start of the tank’s life, and wrongly assume that once that’s out of the way it’s plain sailing.
Testing for the chemicals associated with old tanks needs to be performed weekly, or fortnightly at least. Nitrate, GH, KH, phosphate and pH are all reliable indicators for the health of your tank. At an absolute minimum, nitrate and pH need to be closely watched.
Start by testing your water supply, whether you use tapwater or RO mixes purchased from a store. Unless you are deliberately altering the water in the tank with acidic products like Catappa leaves, then a difference of 0.5pH between the aquarium and the water source is a huge cause for concern. Nitrate levels always need to be low, but if the tank water tests at 40ppm greater than the water source, alarm bells should be ringing.
If you test for phosphate, then levels in the tank should be no higher than 0.5ppm greater than those in the water source. At 5ppm or more, action is essential.
GH and KH levels in the tank should be no more than a couple of degrees lower than source, though it’s likely that KH will deplete faster out of the two. Unless you’re keeping incredibly softwater fish, a tank reading below 5°KH is a warning that cannot be ignored.
Testing is one thing, but the actual process of prevention counts for even more.
The way these issues are avoided is simple: water changes, gravel cleaning and maintenance. There’s no short cut here, and no way to avoid the inevitable. Old tank syndrome is caused by a lack of tank care, plain and simple.
Water changes will fix most things. Taking old water out and replacing it with fresh will dilute down the levels of nitrates and phosphates. Because the newer water will be richer in minerals, it will also help to boost hardness, increasing the GH and KH, and stabilising pH.
If the tank is in a bad way, then opt for a course of small changes — one won’t be enough. Changing 25% daily or every other day will slowly bring things back to where they need to be.
If things really are extreme, to the point of a tank crash, you may want to perform a larger change of 50–75%, though this is a drastic measure. Adding a mineral product such Tropic Marin Remineral Tropic will help instantly boost the GH and KH. An excess of ammonia in the water may be treated with the likes of API Ammo Lock. Nitrates and phosphates can be reduced by using dedicated resin media placed into the filter.
Essentially, all of these points need to be tackled at once. Addressing nitrate levels while the pH plummets is like washing a car while the engine is on fire.
Cleaning gravel is paramount to avoiding OTS. All of the 'hidden' waste down amongst the substrate will gobble up carbonates, and churn out more nitrates than a rotting tree. Left too long, aquarists can even face the rare but lethal hazard of hydrogen sulphide production, where oxygen levels in the gravel drop so low that the 'wrong' kinds of bacteria can proliferate.
A simple gravel syphon will keep on top of this collected slurry. Using a cleaner like the Fluval AquaVac+ will pull up much of it, though it’s just as easy to combine gravel cleaning with a water change and kill two birds with the same stone.
Maintenance is essential, especially for the filter and any plants. Filters accumulate waste much like the gravel does, while some media which removes the likes of nitrates can become exhausted and release much of what it has trapped back into the tank. Frequent changing of resin media, and regular cleaning of sponges is vital.
Plants can also contribute to OTS if kept poorly. Old leaves may drop or degrade, and then they’ll start to rot — meaning more carbonate depletion and more nitrates!
By combining regular water testing with regular water changes and maintenance, there’s no reason for anyone to suffer from old tank syndrome.
You never know, those basic chores might even save you from having an embarrassing fracas with your retailer one day over dead fish..
Potential causes of OTS
- Inadequate water changes.
- Overstocked fish levels.
- Dirty gravel.
- Uneaten food.
- Unwashed filters.
- Dead fish/shrimps/snails.
- Decaying plant matter.
- Low GH or KH water supply.
- High nitrate water supply.
One of the UK's best known discus breeding and showing celebrities shares some of his secrets to success. Nathan Hill meets 'Chen' of Chen's Discus.
"I’m fish rich," says the man offering me tea in his kitchen. He apologises that it’s not too good — he never makes the stuff for himself. But frankly, I’m too preoccupied with the amazing fish next door to notice.
As a journo doing the rounds, one name gets dropped around me more than any others in conversations — Chen. Chen’s fish have a reputation of being some of the hardiest and most vibrant selectively bred fish the UK trade has to offer, and I’d be hard pushed to disagree. The lines of tanks that dominate his two fish houses are bursting with all the colours of a dissected rainbow, while curious but sanguine faces press against the glass like greedy carp. His fish are as fearless as they are dazzling.
As a hobbyist myself, and one who has lived through the near-religious fervour of Chen-worship and mystery, I was taken by a stark revelation about the man behind the legend. He’s not called Chen. Francis Hu, Chen’s founder and owner isn’t even entirely sure himself how the name stuck — it was originally his mother’s surname, but beyond that it’s hazy.
Despite becoming an aquatic legend, he’s as human as I’d hoped. A hobbyist above all else, with a long history of fishkeeping, he’s been around fish his entire life, with a tank of his own guppies by the age of five; he was a precocious fishkeeper.
"Guppies used to be strong," he tells me. "But now wild discus are hardier than they are." I’d ask him to back up his claim, but he already has by showing me his pristine wild discus happily foraging and spawning.
In 1994, he started keeping discus for the first time. He had an uncle who’d bred some that same year, and Francis became transfixed by them. He’d venture out with his brother, and they’d be rapping at their local shop’s door at 6am awaiting the new fish, which they’d select straight from the bags and race home with.
He had to hide them from his mother who was against them buying fish, and had them stashed in a side room. One day their plan was rumbled, but quick thinking got them off the hook. "We convinced her that we bred them," he says with a laugh. That simple lie was a premonition of what would follow.
What started low key as a hobby grew and grew. He insists his interest is breeding and keeping, and downplays any commercial side of his operation. His thing is fish first, business second.
His main role is as a college lecturer, in a part time and consultancy role. He was full time but cut back to just two days a week to give himself ample fish-house time.
"It was back in 2002 or 2003, I just had a night-time epiphany,” he says, "and I thought why aren’t I doing discus as a business?
"I had some good Malaysian contacts and started importing them. Then friends began asking me about them, and buying them from me. It grew from there."
A cursory count up of his facilities now puts him at over 80 tanks, from 45cm/18in cubes, up to 150cm/ 60in lumps, spread out on a variety of racks — and a pond.
A pond for discus
The pond is the most curious thing I’ve seen. With a 500 l/110 gal capacity, and fed by his home-made trickle filter filled with K1 media and foams above, the thing is packed with the compressed, flattened bodies of the fish, yet Francis can tell each and every one apart. I try to round up a number, but there are simply too many.
This was originally built for stingrays, but is now a gigantic (if well stocked) rearing pond for his show fish. To give a little perspective, this one collection alone consumes around 1kg of beefheart mix every single day.
Using a long net, Francis deftly hooks out previous winners and up-and-comers, showing me the subtle differences between them.
"Females lack the show-quality blue vibrance," he says, pulling out fish after fish to make his point. "For blues, the males make much better show fish. For red, you want the females."
Pressed on it, he tells me about the beefheart that he feeds profusely to his fish. "I get through at least four or five kilos every day," he says. "It’s not just beefheart though; there’s mussel, spinach, spirulina, flake, prawn — all sorts in there. It’s what I feed exclusively. It’s actually made by Ditone Discus, which I sell," he adds with a grin. "I must sell a good 100–150kg a month right now…
"Discus need big and meaty foods. Giving them anything else is like us trying to live on baby food. And I don’t use bloodworm. That’s bad for discus as it carries pathogens."
Francis puts food down as the second of his ‘big three’ to discus success. "You need good fish to start with," he says, "and then you need to feed them good food. After that you need good water, by which I mean fresh and clean. Don’t get bogged down by obsessing over parameters."
Making a champion
"Traditionally the UK has been seen as bad for discus," Francis says. "But as of a few years ago, we’ve started cleaning up the international contests."
He’s definitely helping to change the UK perception. Last year he journeyed to a Spanish contest and picked up over ten awards for his fish. He turned up with so many different coloured fish they started calling him ‘Rainbowman’. The year before he only took three fish — and took first, second and third place respectively with them.
Planning in advance is essential, and Francis has his ideas set up to three years before a show. "It takes 16 to 18 months to get a show fish to grow to a good size," he says.
Next year he expects some 20 or 30 fish to come out of his pond in show condition, and they’ll be travelling all over; he has contests lined up in Singapore, Spain, Italy, Holland, France as well as here in the UK. With such a predicted winning streak, it’s not surprising that others want to affiliate with him, and Chen even has an alliance with a member of Qatar’s royal family, representing a prince in European contests.
So how does he do it?
Francis secures his bloodlines from Malaysian breeders, when not rearing his own fish. In 2007 he flew out to see them after some issues of consistency — what they thought he wanted wasn’t exactly the case. They listened to what he had to say, and he showed them how he liked fish to be fed, handled, packaged and kept. He instigated protocols and initiated record keeping in every sphere.
"We’ve got a good rapport now," he says, "and I can ask for fish and they immediately know what I’d like. They steer me away from anything I wouldn’t like. Since I went over, I must have had at least 70 shipments from them."
Key to his success is refusing poor quality fish. Francis has a very clear vision in mind of how a fish should look, but he also knows that if he accepts any chaff then he’s setting up a bad precedent for the future.
"Buy a bad fish and you’ll be trying all the time to recover it," he says. "Lots of people make this mistake, then after a while they give up because of their bad fish, and perpetuate the myth that discus are hard to keep.”
"My first priority is for shape. Discus should be a perfect round shape, or as near as possible to that. Spherical is good. If it’s not shaped like a disc, then don’t call it a discus.
"My second priority is colour and markings. They need to be uniform and intense to win me over.
"The third priority is for eye colour. I prefer fish to have an intense red eye, though not all strains have this."
This order of ranking varies from nation to nation, it seems, with European breeders placing more emphasis on pattern and eye colour first, then breeding those fish to the shape they require.
"There’s an expectation of good fish that differs between keepers, too. Some like colours, while others are interested in good shape."
Francis has simple advice for those wanting to grow their fish on to show standards. "Water changes,” he says, “are essential for good growth. I aim for at least 50% every other day, and my pond gets a 90% water change daily.
"Water changes are directly proportionate to good growth and good health, and they’ll fix many major ailments like fish not feeding."
So simple it’s perfect
Despite many people claiming discus to be delicate, demanding fish, Francis uses the barest of essentials to keep his in pristine shape.
Throughout his multiple racks of tanks, the filtration theme becomes obvious as a simple staple — sponges, wool and some K1 media floating about in trickle towers. That’s as advanced as it gets.
For those imagining his water bill to be skyrocketed by the vast wastage of a heavy-duty RO unit, you’re also mistaken. Everything here is kept in ordinary, everyday Harrow tapwater.
"A lot of Malay breeders are Buddhist," Francis says, "which means they won’t cull any of their fish; they’re pacifists to the extreme. Instead they release their inferior fish into lakes. The thing is, there are people the other side of these lakes then catching them out for the hobby.
"The interesting thing in Malaysia is that only B-grade discus are on sale. All the A-grade stuff is exported."
With as many fish as there are at Chen’s, hygiene is essential. "There’s a disease out there simply called 'discus plague'," he tells me, "and nobody’s really certain about the diagnosis. But if you get it you’ll have 90 or 100% mortalities. Some keepers testify that it can travel about in the air, but I’m not so sure. Early signs are clamping of fins, darkening of the body, lethargy, refusal to feed, that kind of thing. By day four of infection they’ll be huddled in the corner. It seems to be a mixture of protozoan and bacterial infections.
"I sterilise my hands even after a handshake now, it’s just too high a risk not to. It only needs a drop of water, and that can be carried on a plant, or net, or whatever."
It’s the fear of this illness that has Francis putting all fish through a mandatory one-month quarantine. "If it meets a naïve fish, it’ll go down with it fast. I keep everything under a one-month observation, especially if fish have been exposed to cold in transit. They need time to get fed up and used to the UK water."
He’s wary of another discus killer, too. "It’s usually misdiagnosed as discus plague — the difference is that plague makes your water smell. But velvet disease is nowhere near as bad, with only 20% mortalities or so.
"Internal flagellates need to be watched out for. Fish will stop eating, and become shy. Then they’ll have fluffy white faeces.
"It’s when the immune system stops that the worms cut in — often if the fish haven’t been feeding for a while. But it can also be bad water, bad food, or just an underlying problem in the fish. This is why you shouldn’t buy bad fish.
"Kusuri discus wormer will cure it, but metronidazole is better. You’ll need a vet to get that though. And you’ll still lose quality and not recover all the fish. It’s very reliant on the keeper, and people with good husbandry don’t get it.
"There’s a big difference between worms and flagellates. If faeces are white and segmented, you have worms, and you’ll need praziquantel. If faeces are fluffy and the fish aren’t feeding, you’ve got the flagellates."
I ask if his customers ever have fish issues. "Not from bad fish," he says, "but from mishaps. I help out where I can though. As I said before, I’m not exactly fish poor.
"Sometimes I’ll raffle off fish for charity. We had one a little while back that raised £600 for cancer research. Others got on side, like CE essentials and Ditone food, and Devotedly Discus. We’re a good community, and I can afford to give the occasional fish away.
"But it is an expensive hobby," he adds."I’ve got a lot of personal fish, and they’re not cheap to maintain."
Taking a last look around, I’m inclined to agree. Francis may have poured a lot of money in to his passion over the years, but on the back of it, he’s not fish poor at all. In fact, a lot of folks would consider him one of the richest men alive…
Chen’s prices start at around £10 for a 2.5in hobbyist’s fish, while average 5-6.5in adults command between £75 and £100 each. For show fish or competition calibre fish, prices can sit anywhere between £180 to £900. During my visit, one intense yellow discus priced at £700 awaited collection that day.
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The International Aquatic Plants Layout Contest saw a record number of entries this year. Here are some of the aquascapes that made it into the top 20 along with the judges' comments. Check out the February 2015 issue of PFK for this year's Top 7.
Truong Thinh Ngo, Vietnam
Title: Nature’s Melody (pictured above)
Aquarium: 120 × 45 × 40cm/48 x 18 x 16in.
Comments: This layout features the bold use of large, thick driftwood. A dynamic aquascape is successfully achieved by bringing out the best of the driftwood. Its arrangement of aquatic
plants mainly using epiphytic and tape-like species produces a natural feel. Large angelfish make this aquascape more powerful and impressive.
Nichole Wong, Hong Kong
Aquarium: 120 × 45 × 45cm/48 x 18 x 18in.
Comments: Unique stones are used as a layout material. A good balance in the size and arrangement of stones leads to a great presence of the composition. The cosmetic sand from the foreground towards the inner side of the centre adds a bright touch and
depth to the layout and further emphasises the stone composition. Aquatic plants used match the texture of the stones.
Chao Wang, China
Title: Kingdom of Spirits.
Aquarium: 150 × 55 × 45cm/60 x 22 x 18in.
Comments: Thin trees stretching the length and breadth of this layout are reminiscent of ivy and aerial roots hanging in jungle. The trees are entwined so that not even a hand can get through, giving an impression sight of untouched nature in a lush jungle. Two lines of cosmetic sands followed by an open space add a bright touch.
Masashi Ono, Japan
Title: Beautiful autumn.
Aquarium: 114 × 52 × 52cm/46 x 21 x 21in.
Comments: The use of different colours of aquatic plants is impressive. The contrast of bright red stem plants and dark green mosses is very beautiful. The composition surrounded by stones produces a unique visual effect and the shade of stone firms up the impression of the aquascape. Sawbwa resplendens add grace to the aquascape.
Serkan Cetinkol, Turkey
Title: Meet up the winds.
Aquarium: 120 x 45 × 45cm/48 x 18 x 18in
Comments: This layout depicts a realistic landscape of a lake surrounded by forest and sheer rock mountains. Perspective is emphasised by the contrast of the large tree in the left front and the forest at the back, creating the illusion of a natural landscape. It feels undeniably odd to see fish present in such a terrestrial landscape.
Katsuki Tanaka, Japan
Title: Great waves of wilderness.
Aquarium: 120 × 45 × 45cm/48 x 18 x 18in.
Comments: The repeated use of driftwood in the same pattern is impressive. Perspective is emphasised by the contrast of large driftwood in the front at both ends and very small pieces at the back in the centre. Mosses attached to the driftwood create a unique atmosphere reminiscent of dense wood.
Hironori Handa, Japan
Title: The world behind peacefulness.
Aquarium: 120 × 45 × 45cm/48 x 18 x 18in.
Comments: An aquascape is expressed using driftwood and stem plants. This layout uses a classic concave composition, but a depth is naturally created towards the open space by the driftwood arch in the centre. Aquatic plants are n a good balance and the fish match the aquascape well.
Julien Voultoury, France
Title: Hades’ breath.
Aquarium: 120 × 40 x 50cm/48 x 16 x 20in.
Comments: The combination of stones and driftwood gives a wild impression. The layout is broadly divided into three parts, and perspective is expressed by making the centre a near view while the both right and left sides create a distant view. The use of mainly epiphytic plants such as mosses and ferns emphasises the wild feel of this layout.
Robertus Hartono, Singapore
Aquarium: 90 × 45 × 40cm/36 x 18 x 16in.
Comments: Perspective is skillfully expressed by a bold arrangement of driftwood and winding flow of cosmetic sand. The planting and the combination of stones and driftwood are very natural. The fish also match the atmosphere well. However, the aquascape would have looked more natural without the waterfall.
Olivier Thebaud, France
Aquarium: 120 × 60 × 60cm/48 x 24 x 24in.
Comments: The composition, made of a bold arrangement of large driftwood, is powerful and effectively expresses the perspective. Splendid balance of colour is achieved with reddish wood, white cosmetic sand and green aquatic plants. The use of roundish stones skillfully expresses a river bottom.
Jiraporn Sripraserth, Thailand
Title: Medicine cabinet.
Aquarium: 180 x 60 × 50cm/72 x 24 x 20in.
Comments: This layout is reminiscent of scenery of Guilin, China. A landscape of many odd-shaped rocks is depicted by standing stones in a panoramic aquarium. Expressions of landscape and aquascape are perfectly blended.
Jian Feng Zhang, Macau
Title: Great momentum.
Aquarium: 120 × 50 × 50cm/48 x 20 x 20cm.
Comments: This layout uses stones featuring characteristic red and white stripes. A terrestrial landscape is skillfully expressed by the arrangement of different sizes of stones to emphasise perspective. With the effectively planted mosses, the exposed stone surface looks exactly like a real cliff.
Atsushi Suzuki, Japan
Title: Delightful green.
Aquarium: 124 × 48 × 56cm/50 x 19 x 22in.
Comments: Skillfully depicts a natural feel using stones and driftwood. The shadow below the stones and the driftwood entwined around the stone add a natural depth. Well-balanced composition, effectively-made open space and cosmetic sand create perspective and flow of water.
Tristan Lougher explains why it pays to be prepared before stocking the tricky Powder blue surgeonfish.
Common name: Powder blue tang (surgeonfish).
Scientific name: Acanthurus leucosternon (Ack-ann-thur-uss loo-co-stern-on).
Size: To 23cm/9in.
Origin/natural habitat: Reef flats of the Indian Ocean from the east coast of Africa to Indonesia. Reported also from Bali in the Western Pacific.
Tank size: 400 l/88 gal plus.
Water chemistry: Ammonia and nitrite should be zero. Stable pH 8.1-8.4 is advised. Nitrate should be below 25ppm, ideally lower.
Approximate lifespan: Five years plus. Specimens kept well should live into double figures.
Sexing: External sexual differences have been reported such as nuances in body shape and pattern, but these are not discernible in any but the largest most mature fish where females are substantially larger than males.
Spontaneous purchases of marine fish can work but often don’t. There are so many species to choose from already, and there are several new-to-the-hobby species being imported every year. So, it’s perhaps unsurprising that aquarists can encounter fish they have never seen before in their dealer’s aquaria.
However, there are many fish that are instantly recognisable and about which there is an abundance of information.
Popular because of their ravishing good looks, affordability and widespread availability, one might be forgiven for thinking that they are easy to keep too. While by no means impossible, they can present unprepared aquarists with serious problems. However, a little background research and planning means that an aquarium can be established that provides for the specific needs of these fish in the long-term.
The Powder blue surgeonfish is many things: iconic, beautiful and yet potentially frustrating when it proves difficult to keep. Establishing an aquarium that addresses its particular needs and potential problems from the moment of its conception through to design, construction, then finally stocking is a way of avoiding many of the potential problems with this beautiful surgeonfish. Of course, most Powder blues do not have their entire system designed around them and they can still thrive in mixed systems. However, many aquarists have learned the hard way not to impulse buy one. Most of the key points that help aquarists to achieve success with this species are applicable to any aquarium, but for those wanting to recreate a little slice of nature, the reef flat aquarium is a great place to start.
In common with many surgeonfish, the Powder blue surgeonfish will fiercely defend areas of macroalgae from competitors or indeed any fish it perceives as a threat. In its natural environment, it may have to see off marauding shoals of the rival surgeonfish such as the Convict surgeon, Acanthurus triostegus, with aggressive attacking use of the scalpel-like scales located on its caudal peduncle. Although large shoals numbering hundreds of Powder blue individuals are also seen with regularity, it is generally intolerant of members of its own species and, at the margins of their territories, pairs will display and skirmish with rivals.
Its laterally compressed body shape and low-slung mouth are ideal for getting into nooks and crannies to remove algae, and it will busily swim throughout its territory searching for food. Here it might form loose associations with other species of surgeonfish including members of the genus Ctenochaetus, the bristletooth tangs. It has been suggested that this form of tolerance of similar species is convenient to each, as it increases the chances of new browsing sites being found and also offers some safety in numbers from predators.
Stop problems before they start
Researching potential issues with fish before establishing an aquarium for them allows the aquarist to manage problems before they occur. Aquarists that aspire to maintain the powder blue in the short, medium and long-term must address and solve each of these problems through system design and careful selection.
1. Their tendency to invite disease when stocked into their new home. They invariably contract Cryptocaryon (marine white spot) between two and ten days after being introduced.
2. Specimen selection: Is it feeding? Is it healthy? Of course, these types of questions can and should be asked of any fish before purchase, but for some marine species, identifying those individuals that are bold and greedy in their feeding behaviour can make their transition to the home aquarium an even smoother one.
3. Their territorial nature: many marine fish are territorially aggressive and the Powder blue isn’t the worst of them. It isn’t even the worst surgeonfish, but the same instincts that drive it to defend it’s patch of alga from raiders can kick in in the home aquarium, and in a closed system this can lead to serious injuries being sustained by its tank mates.
Buy better fish
Although research and planning are essential when selecting fish species for inclusion in a saltwater aquarium, it is vitally important that decisions concerning the actual specimen to be stocked into your aquarium are based on the individual rather than the species. Hopefully, you will already have determined whether the species itself is suitable for your particular aquarium, and that includes both hardware and species stocked/to be stocked.
Try to see a number of Powder blue specimens before you buy one. How do they compare with specimens you saw during your research? How do they compare with wild photographed fish? This should help give you a feel for the species, how it looks in a dealer’s aquarium and some understanding of what to look out for in the individual you end up buying. It is also useful to decide whether a smaller or larger individual is better stocked in your particular circumstance, and that might be influenced by the size and disposition of the other fish to be stocked.
When it comes to the time to buy, ensure that you see it feeding before you commit to the purchase. Ideally, it should browse on algae (dried and/or natural forms) in addition to meaty offerings such as Brine shrimp or Mysis.
Avoid individuals where the spine is visible; it’s possible to reverse the weight loss incurred when fish are collected and shipped and this is likely to occur when fish are fed sufficiently well on quality foodstuffs. However, this is a variable that the new Powder blue owner doesn’t need, and having high standards during the selection process should increase the chances of success.
Occasionally, specimens that are feeding well on flake and pellet diets can be found, and those are likely to be the best settled. Ask how long an individual has been in residence at the dealer’s; the better individuals are likely to have been in stock for a number of days or weeks.
How do we define 'better'? It’s not all about colour although that too can be an indication of health and vitality. Sometimes fish held in intensive marine fish-only systems can lose a little colour over time. The good news is that if the aquarist prioritises the fact that they are feeding well and have recovered from shipping over vibrancy of colour then the intensity and beauty of their colours should be regained within a matter of days in most instances.
Add tank mates first
The benefit of the creation of an aquarium that provides for the needs of fish that can be classed as 'tricky', is that more straightforward species will usually benefit from the extra planning and enhancements to the system. For example, surgeonfish are not the only species to suffer from white spot infections and therefore inclusion of a UV benefits all newly introduced fish. Establishing the aquarium to be sympathetic to the fish’s natural environment could even inspire the aquarist to pursue the biotope aquarium where the sunlit reef flat fauna is recreated to an extent.
The good news is that the Powder blue will live with almost any tank mates given sufficient time to settle in a new home, but its territoriality can be an issue. The willingness to form schools with other, similar algae-grazing species in the wild is not something to be attempted lightly in the aquarium. Indeed, it can be best avoided altogether. Their intolerance of competitors for algae might be understandable, but less easily explained is their apparent hatred of butterflyfish. None of these blends of fish groups are impossible to recreate in the home aquarium but perhaps best avoided in a system where the well-being of the Powder blue is a priority.
Bear in mind that the territorial nature of this surgeonfish is likely to be enhanced by the aquarist offering meagre rations; an approach often adopted by aquarists who understandably want to prioritise their water quality. One of the best ways to avoid conflict is to make this the final large-fish addition to the aquarium, i.e. after all of the other species have been given a chance to settle over a number of weeks. This might not eliminate territoriality entirely, but it should reduce it. That, together with some suitable choices for tank mates can make all the difference.
Another possible solution to the stocking of territorial species is to stock all potentially aggressive species simultaneously and as small juveniles. In the case of most surgeonfish and tangs, which may compete for natural algae resources in the aquarium, there may be limits regarding just how small the specimens available to be stocked are. At least adding them at the same time means that they are all in the position of having been stressed while being moved to their new aquarium and will settle in at similar rates.
This is particularly useful when stocking surgeonfish that are even more territorially aggressive than the Powder blue: surgeonfish such as the Red Sea’s Sohal, Acanthurus sohal, and the Indo-Pacific’s Clown, A. lineatus.
Smaller, busy fish such as anthias (Pseudanthias spp.), damselfish (Pomacentridae), dottybacks (Pseudochromis spp.), fairy wrasse (Cirrhilabrus spp.), peacock wrasse (Macropharyngodon spp.) and flasher wrasse (Paracheilinus spp.) are all suitable groups with which Powder blues will mix with the minimum of conflict. Stock larger fish such as dwarf angelfish, larger wrasse and angelfish before the Powder blue. Of course, any species choices will also be influenced by the variety of sessile invertebrates, if any, that are also stocked.
For the majority of specimens, once the first month in their new home has been successfully negotiated, they will go from strength to strength. However, water quality must be maintained to high standards and care must be given to the diet of the surgeonfish. Given that the Powder blue is one of the last fish stocked into the system, at least the last fish of any size that should be stocked, attention will have to be given to feeding all of the other fish in the aquarium too and to ensure that they are not competing too strongly with
the Powder blue.
One of the best ways to offer food to this fish is using nori or other forms of dried alga (dried sushi nori is the form I find most Powder blues accept most readily) on a seaweed clip daily. This should ideally be placed into the aquarium in the morning (or when the daylight period of the aquarium begins), so the fish can browse throughout the day. Meatier offerings can be made; pellets and flake are often accepted by this species, as are familiar frozen diets such as
Mysis and Brine shrimp. There are many other formulations of frozen food containing algal enrichments or high percentages of vegetable material that are also suitable. Keep the diet varied and of high quality, but always offer the dried alga.
How to set up a Powder blue surgeonfish tank
Tank size: 400 l/88 gal is an absolute minimum for this species long-term. It will afford swimming space for this active fish and a water volume that is sufficiently large to afford some stability to the system.
Filtration: For me, the best way to create an aquarium sympathetic to the needs of a Powder blue is to make it a living rock based system. This means the bacteria within the rock itself will provide the biological filtration: the removal of ammonia and nitrite.
Nitrate can be controlled to an extent by other varieties of live rock based bacteria and enhanced through the use of carbon dosing, whether with liquid alcohol based products or through the use of bio-pellet reactors. A good-sized, efficient protein skimmer is essential whether carbon dosing is employed or not.
Water currents and their intensity will be determined by the species of coral where stocked, but Powder blues do seem to enjoy areas of vigorous water movement provided by stream-type pumps, as long as they have areas where they can find quieter water.
Equipment: You are going to need an ultraviolet (UV) steriliser. You might be one of the lucky people who stock a Powder blue that never develops a protozoan parasite such as white spot (Cryptocaryon) or marine velvet (Amyloodinium), but that would place you in the minority of aquarists with experience of this species.
Thinking you might get lucky is a big mistake, and why endanger the life of not only your Powder blue, but also the rest of your stock, as the aforementioned parasites are highly contagious and potentially lethal. This, coupled with the fact that treatment options in a reef aquarium containing live rock and corals are extremely limited and it becomes clear that the UV cannot be seen as an option; it’s compulsory. Prevention is always better than cure in these situations, and running the UV when the fish is introduced to the system and for a period of three to four weeks subsequently will increase your chances of success with this fish.
If you plan on keeping corals in the Powder blue aquarium, and there is no reason why you shouldn’t, then the lighting will need to be adequate for the species/varieties chosen. LED illumination gives that authentic rippling light effect that is such a prominent part of the shallow reef experience. Although the current trend for high percentages of blue light in stony coral aquariums enhances the fluorescent proteins in their tissues, lower Kelvin ratings will afford a whiter light that will showcase the fabulous colouration of the Powder blue as well as faithfully recreate the shallow water in which this fish is commonly encountered.
Aquascaping: Powder blue surgeonfish adore swimming space. In this system, building a shallow incline of reef at about 30 degrees to the horizontal affords plenty of open water and yet still lots of rocky substrate over which the fish can browse for algae. Alternatively, you could opt for a horizontal arrangement of rock with one or two sand or rubble patches that would recreate the reef
flat zone nicely. Corals can be widely spaced giving focal points of interest with plenty of exposed rock over which the fish can browse.
Quarantining is a hard process to argue against for any fish, saltwater or freshwater, but reality dictates that few marine aquarists have the budget and space to establish a system into which fish can be placed, observed and treated and therefore don’t own one. Lack of quarantining is another one of the reasons why a UV steriliser is an essential piece of kit for the Powder blue.
Most fishkeepers consider keeping Zebra plecs and many would like to breed them. But whatever your goal, you'll need to know to look after them, says Julian Dignall.
The only thing black and white about the Zebra plec is its beautiful markings. Pretty much everything else is subject to myth, opinion and misinformation.
This, as well as the beautifully contrasting stripes, do add to the somewhat legendary status the Zebra plec, Hypancistrus zebra,
Depending on whom you speak to, the Zebra plec was discovered by anglers somewhere between the mid 1970s and 80s. It was given an L-number, L046, in 1989. The stripes of the Zebra have come to represent a new wave of catfish keepers, and it’s a flagship species for the now undeniable fishkeeping tribe that are L-number keepers and breeders.
The Zebra plec is endemic to the middle of Brazil’s Rio Xingu (pronounced sheen goo) and is among the catfish species at risk from the Belo Monte dam.
It lives at a depth where the surroundings are, at best, pretty gloomy, if not completely dark. It lives in the cracks, gaps and natural caves found in the very specific type of rock found in the river.
This is dark brown to black hard igneous rock that, in shallower water, is set in tan-coloured sand. There is very little submerged wood, there are virtually no plants and the water belts through the area at a rate of knots. Many of these areas are rapids and the water is highly oxygenated.
Exports of tropical fish from Brazil are governed and policed by the Brazilian Institute of Environment and Renewable Natural Resources (IBAMA). IBAMA produces a so-called positive list of fish species and those are the ones that may be collected and exported into the global ornamental fish trade. Hypancistrus zebra has not yet appeared on it and is illegal to export from Brazil.
When you encounter one for sale it will either be captive-bred or will have been smuggled out of Brazil and exported, typically, from Colombia. They range from around £95-£150. This activity, as you may imagine, stirs some debate among fishkeepers. Even if such a wonderful species is at risk of extinction in the wild, does that make it acceptable to fund the smuggling of them into our shops? That’s to say, 'rescue' them before they are wiped out.
Thankfully, the Zebra plec’s future looks a bit brighter than many of its Xingu river cohorts. Because of its small size, relative ease of breeding and status, it is bred and traded in most countries that have a decent aquarium hobby.
In the aquarium
Keeping Hypancistrus zebra is straightforward, especially with captive-bred stock. When this species was first being bred in aquaria, arguments raged over how to best keep and breed it. Some polarised views were initially stated, but it turns out most folks were right, even if they had different points of view, because this species can live in a range of water conditions.
So, the hard water proponent was no more right or wrong than their softer water advocate. It has been bred in really quite hard water with no ill effects, though most spawns are in about pH 6.5-7 with moderate to no hardness.
I accept that breeding fish isn’t everyone’s cup of tea. It’s not a view I subscribe to personally, but I get the fact that people just want to look at their fish rather than reproduce them. However, in the case of the Zebra plec the majority do wish to breed them.
This may be for any mix of anticipated financial gain, fishkeeping kudos or the positive feeling gained from furthering the chances of this species’ ability to survive for future generations. So, let’s talk about how to keep them so that they breed and then, if you remain convinced you don’t want to breed them, you still have the intel on how best to keep them
Provide warm, oxygenated and clean water. Aim for a neutral pH, a water temperature of 86-88°F/30-31°C and have at least two power-driven filter outlets that mix in atmospheric air with the water flow. Clean water means both a decent power filter and at least 25% water changes.
Consider using plants and bogwood to replicate the natural habitat.
Feed them right
Feeding is more a matter of physics than biology. Zebras are not large plecs and you can keep a group in a relatively small tank. However, with all that filtration in play (see box above, right) food can get blasted around the tank and filtered away before the fish get to eat.
This is where some trial and error with aquascaping comes in. Play around with rocks so that there are some open areas of gravel where food collects. Even better would be near caves. If you can, do this in such a way as it’s easily accessible.
It may sound obvious, but be really careful moving rocks around with plecs in the tank. It is easy to trap or squash them, especially if you are stretching or off balance.
Aim for an aquarium that allows food to sink to quiet pockets away from the current, where the plecs can feed over a ten to 15 minute period once or twice a day. The choice of food is important. Flake or floating foods won’t do well in that kind of current, so sinking tablets made from flake or algae tabs will work, but Zebras need a lot of protein. I favour discus food, either frozen or granular. Select one that doesn’t expand a lot once placed in water. Many plecs will gorge on whatever food is available and something that expands to twice its size after being submerged for five minutes is remarkably lethal. This is especially true in plecs, as two thirds of their bodies are covered by rigid plates, so the only way the stomach can expand is downwards where there is only exposed skin.
Keep discus separate
The temptation to keep Zebras with discus is strong, as they share water requirements and similar diets. But the issue of water current can be overlooked. If you’ve got a filter that provides lots of dissolved oxygen (but without the kind of current that would scatter the discus around the tank), then this might work but it’s a bit hit or miss.
If you’ve a central system, then keeping Zebras in one tank and discus in another in the same system would work well, as you can add a pump/filter to the Zebra tank to create the extra current, but I’d suggest keeping these two fish apart in the main.
I like to keep plecs in oversized tanks because it means I have a lot more flexibility when it comes to looking after their water. For example, I have a group of five Zebra plecs breeding in a tank that has a 91 x 46cm/36 x 18" footprint and is 38cm/15" high.
In this is 2mm bore gravel to a depth of about 1". I mix black and brown gravel to get a look that I like and it appears the Zebras are, at least, not objectionable to. The black and white fish look fantastic against what is not only attractive, but reasonably natural substrate. On top of this, I have lots of breeding cave pipes and then slate and lateritic holey rock.
Zebra plecs won’t breed unless caves are present. These are commercially available or you can make your own. As a rule of thumb, I put two caves in for every adult fish. This is seen by some as overkill: some authors have one cave. However, I note a lot of aggression over caves and the alpha male will always pick the one that suits him best. So, if there are others available, the fighting is toned down a bit and, like me, you might be lucky and get two pairs spawning. This is relatively unusual, and it’s more common for males to breed with more than one female, a few weeks apart, but in the same cave. Females will live near the male’s cave, and so I like to provide rock cover over the caves that are thus in shade.
The temptation is to have them in full view so you can monitor proceedings, but it’s more important to have the cave mouth perpendicular to the current and for all the adult fish in the tank to be able to come and go from their places of rest without too much aggro.
Get the décor wrong and adult male Hypancistrus can seriously injure and kill each other. However, many people buy captive-bred Zebra plecs and they tend to be a bit smaller and not yet mature. Thus, such aggression has yet to manifest itself and can be avoided altogether by adding refuges as the fish begin to mature.
Sexing your zebra plecs
In well-conditioned, mature fish, sexing is straightforward. Applying these observations to fish less than about 80mm SL or that have not been in captivity for long will give variable results.
1. Full-grown male Zebro plecs are about 10-15% larger and bulkier than females.
2. The male’s interopercular odontodes that have grown from the fish’s cheek under the eye are longer — more than two times the width of the eye.
3. The male’s leading pectoral fin spine has orange-tipped odontodal growth of a similar thickness, if not length, to the cheek spines.
4. Males have heavy-set heads.
5. When viewed from above, males have a straight line from the base of the pectoral fin spine to the caudal peduncle.
6. Flip them over and examine their pinky-white undersides: males have pointier bullet-shaped genital papillae.
7. Females are generally slighter.
8. While females develop cheek and pectoral fin spines with maturity, they are shorter and less noticeable than the males’.
9. Females have a convex, curved outline from the base of their pectoral fin spine to the caudal peduncle (broadest in the midriff where eggs will be developed).
10. Underneath, females have a much less defined, but broadened genital papillae.
Much debate surrounds spawning triggers. Some authors report that not cleaning the filter — therefore slowing the water current a little — along with skipping a water change or two followed by increased water changes triggers well-conditioned pairs to spawn. Many say they will start spawning when mature given good water conditions. Certainly once they do start they will continue for years.
Often the first batch of yellowish orange eggs will be infertile and not hatch. This commonly happens with many plec first timers. It’s just a sign to keep doing what you’ve been doing — within a month, they will try again, maybe sooner.
The male will normally guard the eggs in the cave and often the first an aquarist knows they’ve bred is on seeing some delightful mini Zebras scooting around the tank, typically under stones.
If disturbed or inexperienced, the male may displace the eggs out from the cave. In this situation, or where you want to micro manage the eggs hatching, then an in-tank nursery is required. This can be a net mesh box or a more sophisticated plastic box, but the important things are that it shares water from the parent tank and is easy to clean. Place an airstone close to the egg clutch to simulate the fanning of the male’s fins in the cave.
When they hatch, youngsters will have unfeasibly large yolk sacs. It is only when these are consumed that you should start feeding. Crush whatever you’re feeding the adults and consider sinking tablets too. They are not hard to feed and even at this small size will eat dry foods eagerly and regularly. For best results try to feed twice a day or more. Clean the nursery at least daily, it needs to sparkle.
However, I prefer the hands-on dad approach and Zebra plec dads do a great job of getting 20 or so youngsters out of the cave. At this size they will forage and eat with the adults. They’re slow growers and unless you pay them a lot of attention in terms of feeding, space and water quality, getting them to grow more than 1cm every 6-8 weeks will be a challenge.
Zebra plecs are now bred in commercial numbers and these turn out beautiful clean fish in number. Also, shipments of wild-caught fish tend to have more males than females (it’s easier to collect males from the wild as they tend to be in a cave), but with captive-bred fish, it is more like parity. Because these are high-end fish, professional breeders know they must be kept in high quality surroundings to ensure they grow on well and fast.
Zebra plecs produce about 20 eggs and spawn every couple of months. These figures can be improved a little with ultra-attentive care but serve as a good indication. So, one pair could produce about 120 offspring a year. Let’s call that 100 once you take into account culling of inferior fish and the odd accidental loss for whatever reason. Now you need another year to bring them on. That’s running, say, eight tanks for two years before you start selling them. That can be done, but selling them in twos and threes to private buyers isn’t going to fund that Porsche anytime soon.
To make it a business, you’re going to need, say, 100 pairs and several hundred tanks — most of which you’ll be running for a year or two before any selling occurs. Bear in mind that a £100 retail fish might wholesale at about £40 and you don’t make any margin on shipping. Then factor in shipping disasters and so on. At some point in time, heat and food makes it more viable to attempt such an endeavour in a tropical country rather than in chilly old Blighty — unless you really scale up the operation or transport costs rocket.
This is the model being utilised by specialist commercial breeders and I think that given the beauty of the Zebra plec, will ultimately mean we continue to see this species offered for sale irrespective of what man-made catastrophe may, or may not, befall its wild cousins. This is also why I mention breeding this species for yourself. You can get to the stage where you and a group of friends have a decent population of these things and can trade with other groups. Isn’t that a good thing?
Given what I’ve said, perhaps seeking experience, cutting your teeth on less expensive Hypancistrus is a good starting point. If your ambition to keep
these wonderful black and white rock star plecs remains, you’ll be able to give it a worthwhile go and do it in a planned manner. Then you can dream of that first sight of baby Zebra plecs in your tank. That experience is a special thing.
Scientific name: Hypancistrus zebra.
Pronunciation: Hype an siss truss.
Common name: Zebra plec.
Lifespan: 15 years plus.
Spawning age: Around three years.
Water chemistry: 5.5-7.5 pH.
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