Nathan Hill explores the origins, benefits and breeding of one of the hobbyâ€™s biggest game changers, the Amano shrimp.
I’m not sure aquascaper Takashi Amano realised just how much he’d change the face of fishkeeping when he asked a local collector to round up a few thousand bland, colourless shrimp for him. Now, three decades on, there are few tanks that haven’t felt the presence of these hard-working, tenacious invertebrates.
My own experiences with these fastidious grazers have been positive through and through. They’ve saved aquascapes as well as my large retail displays (in my aquatic store manager days) and I’ve even had them breed, which is something I didn’t know was remarkable at the time and something that many Amano shrimp adherents will vehemently deny; more on that later.
The true Amano shrimp is Caridina multidentata, but you might see them bandied about under their synonym of Caridina japonica. Certainly when Takashi stumbled across and popularised them in the 1980s, that was the name they were recognised by. It was only in 2006 that revision took place and gave them their current identity of C. multidentata.
If 'japonica' sounds a little Far Eastern to you, then you’re on the right track. This name refers to their Japanese heritage, where Takashi came across them and where many come from today. The original specimens were recorded from the Ogasawara (or Bonin) Islands, though they’re just as happy on mainland Japan too.
Some folks have the impression that Amano shrimp only come from Japan and its immediate vicinity, but this is far from true. In reality, Amano shrimp are also found in Taiwan, the Ryukyu Islands (between the Philippine and East China seas), Fiji and maybe even Madagascar, though this is unlikely. There was contention over the validity of the Madagascan shrimp. As far back as 1965 taxonomists (namely Dr Holthuis) have been marking them out as different and have cited features such as moving rostral teeth as adequate features that have granted them their own species status.
There’s even the strong chance that some of the Amano shrimp on offer in the trade are not true C. multidentata. Caridina make up a huge genus of approximately 280 different species spanning across Asia, Oceania and Africa — there’s even a Caridina species in Lake Victoria. With such an abundance of species, many physically very similar, it’s easy for imposters to slip under the net and enter aquaria. One shaky train of thought is that many 'Amano' shrimp on sale are not true, Japanese specimens but a Taiwanese variant.
These 'Taimanos' are identified by two features: the first being their shorter, compact rostrum, and the second being their inherent laziness. Supposedly, these false shrimp also breed entirely in freshwater, which is something that C. multidentata do not do. But aside from that they have the same, nondescript colours and similar markings.
There are even hints of an Indonesian variant doing the rounds, but these are also contested on a species level; they have a straight rostrum and not a crested one. Buyers beware, and be diligent. True Amano shrimp should be relentless workers, and that’s exactly what fuels their popularity. Tirelessly padding away with their tiny maxillipeds, they will graze on almost all forms of algae with just the dreaded Black beard algae and some cyanobacteria types being sometimes averse to their palates.
Lacking cutting or biting mouthparts, at best they can softly rasp away at surfaces taking away the topmost film. This inability to cause harm makes them ideal workers in tanks where there are small fish and even fry, which they will largely ignore. My own experiences have seen the occasional, bold Amano tootling off with a prize in the form of a fish egg, but their impacts on breeding populations are negligible at best.
Some aquascapers have griped and bickered that their Amanos have damaged planting, but this is unfair condemnation. Amano shrimp will indeed rasp away at plants but are only able to take away material that is already dead or dying. It’s not unusual to find perfectly cut holes in leaves, where plants have degraded through nutrient deficiencies and the shrimp have cleaned the site up. Much like maggots in a wound, they’ll only eat the bad and leave the healthy.
Second to none
The benefit to the aquarist in keeping these shrimp is huge. Their eating efficiency and digestive capacity is second to none, and, in part, a reaction to what can be an oligotrophic lifestyle.
In the aquarium they will pick up on almost any waste, be it uneaten food, fish faeces, decaying plants, or whatever, and convert it into tiny packages of shrimp waste, almost like large grains of jet black sand. These can then be easily siphoned from the tank during a water change.
Regardless of how good a cleaner they are, remember that Amano shrimp do not impact on nitrate levels at all. It does not matter if you have ten or two hundred of them, you’ll still need to water-change just as frequently!
There’s little reason to consider a biotope for these creatures, but if the idea appeals then simply go in for a large tank with big rocks and boulders inside it. Alternatively, Amano shrimp can be found in swamps with a handful of mossy plants and organic litter.
Don’t be scared of a little turbulence either. In their natural range, Amano shrimp are often subject to middling to strong flows and have a better grip on surfaces than you might expect.
Tolerant creatures (Picture above by George Farmer)
Amano shrimp tolerate a range of water conditions with the exception of the usual suspects that are ammonia and nitrite. Some sources cite Caridina as being indifferent to nitrite, but this isn’t always the case. Although nitrite reacts in different ways to shrimp blood as it does to fish blood (contact with the latter forms the lethal methaemoglobin), at high doses it can still cause a degree of mortality and difficulty.
As well as ammonia and nitrite, heavy metals should be avoided so remove any rocks with striated lines of metal through them and avoid lead weights for plants. Although these become issues in mainly softer, acidic water, even in hard systems they can form dangerous levels.
Aquascapers are occasionally worried about the heavy metals found in plant nutrients, but to my knowledge there is no credible evidence that even a major overdose of ferts causes health issues or fatalities in Amano shrimp.
Avoid salt, too. Though this chemical is essential for the rearing of larval shrimp, the adults have no tolerance of it and even background levels used as tonics (3g per litre) can be lethal to them. Hardness needn’t be high, but GH should not be below 6° for successful moulting. Temperatures are tolerated between 18 and 27°C/64.4°F and 80.6°F, and fluctuations between day and night largely ignored.
One area of caution is the use of CO2, especially where Amanos are in planted tanks. Excess CO2 will drive the pH down, and below 6.0pH they will struggle.
They will go up much higher and all the way to 7.5pH without problems. Above this they don’t fare as well and their lifespans will be shortened. Caridina multidentata are pretty resilient when it comes to diseases and aren’t affected by the gamut of usual fish ailments.
White spot and fin rot is not something they’ll experience. In fact, aside the problems of Planarian flatworms that sometimes fight to get under the carapaces of shrimp there are few health issues. Some commercial shrimp suffer fungal issues and many fancy types carry a small flatworm on top of their heads called Scutariella japonica, a miniature symbiont that does little except eat particles of shrimp food and lay eggs in the gills. Amano shrimp, however, seem rarely afflicted by this.
The biggest danger to your shrimp is poisoning, especially from airborne insecticides and more so from imported aquarium plants that haven’t been properly rinsed. Subjected to these chemicals, shrimp will rapidly turn from transparent to white and/or pink and lose all composure and momentum. Shortly afterwards they will be immobile on the base of the tank with only their tiny pleopods twitching, and then they will die. There is no cure for poisoning once it takes hold, so avoidance is the only sure course.
Keep them correctly and you can expect a lifespan of up to four years from your shrimp, over which time they can reach up to 5cm/2" in length.
Choosing the best filter for the job
Filtration for Amano shrimp needs to be unable to suck them in, but they also benefit from having access to sponge filter media where they will nibble at the biofilm and waste contained within. Foam, air-powered filters are a good choice, but better still is the Hamburg mat. This involves placing an entire sheet of foam within two guide rails to create a filter 'wall'. An uplift is then placed behind the mat, just like the uplift of an undergravel filter, and water pulled through the foam and back over the top into the tank.
Hamburgs provide a huge filtration surface, as well as an ongoing source of food for shrimp, and cost pennies to put together. Your local aquatic store can likely give you more advice and the parts required to put one together if you choose.
How well do your Amanos grow?
All crustaceans need to shed their shell in order to grow, and this stage is called moulting.Shrimp moult more when they are younger and, subsequently, growing faster, though adults may moult on around a monthly basis. This also helps to keep the shell healthy and free of pathogens.
With insufficient GH in the water, moulting is impaired. Some keepers rattle sabres over whether or not to leave the shell in the tank once the shrimp has shed.
In theory, the shrimp will ingest some of their own shells and regain some of the valuable chitin within. But in reality if diet is appropriate and GH levels adequate, then this will be surplus to requirements.
That said, there’s no harm in leaving the shell in the tank for grazing purposes.
Differences between prawn and shrimp
People often ask what the difference is between a prawn and a shrimp, and everyone likes to hold a pet theory about what constitutes each.
In reality there is no difference between the two words, and they are arbitrarily assigned to whatever takes the whim of the user. Scientifically the two names carry no meaning, so you should feel free to call your own tank inhabitants a troupe of Amano prawns if that’s what you prefer. So there you have it. Prawn and shrimp are common names, which vary considerably depending on where you are.
If you’re in America you might be sold prawn as shrimp, and in the UK you’ll get the reverse but it’s nothing deeper than that.
How many legs do shrimp have?
Shrimp belong to the order Decapoda, like crabs and lobsters. The common feature between them is that their ancestral progenitor had, at some stage, ten pairs of legs.
Looking at a shrimp it might appear obvious that nowadays they have anything but ten pairs, but the point still holds. They have just adapted and changed the forms and roles of their legs, so that the ten pairs are now divided up between the pereopods, or walking legs, and maxillipeds, or mouthpart legs. The swimming legs, the pleopods, at the rear end are a different matter altogether and are not classed as legs in the same sense.
Copper and crustaceans don’t mix!
Most medications come with clear warnings that they shouldn’t be used with shrimp and for good reason. Anything containing copper compounds is lethal to crustaceans and needs to be avoided.
The reason it is so dangerous is down to the blood of the shrimp. We humans use haemoglobin, which is basically iron that makes up our blood cells, to carry our oxygen around. Crustaceans, however, have blood cells made up of haemocyanin, which uses copper instead of iron to carry oxygen. When using copper-based medications this blood is affected, ruining the crustacean’s ability to ventilate.
Some keepers are reluctant to use water that has been stored in a hot water tank or run through copper piping for fear of contamination, though this only tends to be reported as an issue in new plumbing systems that have not had the chance to calcify inside. An offshoot of having copper-based blood is that unlike our own, which is red, in shrimp and other crustaceans it is blue.
Breeding antics (Picture above by ãµã†ã‘, Creative Commons)
Caridina multidentata is incredibly difficult to breed. Though the leaner males will frequently engage with the plumper, larger females, raising the larvae (sometimes called the Zoea) requires a marine and brackish stage.
Wild shrimp live coastally, where they release their young downstream into the sea. After some four to five weeks, during which the Zoea frequently moult and fatten up on plankton, they become parva, which move back upstream to restart their lives in freshwater mode. This explains their distribution over so many sea bound islands. As the females become increasingly pregnant (or berried) they will show a telltale darkening in the first segment of their abdomens.
My own Amano shrimp bred more by extreme coincidence than skill of any kind. Kept in a 120cm/47.2" cube tank with diabolically slow flow, the tank and adjoining system would be periodically treated with salt to help new arrival fish.
Also in the tank were large, adult Piranha who frequently bred. With ample surface cover in the form of dense duckweed, I would periodically tap the surface growth while holding a net underneath to frighten the Piranha fry into the net. Each and every time I did that, I would yield around 50 to 100 shrimplets for every juvenile Piranha. My only explanation is that with such slow flow and large volume my tank may have developed a slightly saline 'layer' within it, in which the young shrimp had enough salt to survive. Either that, or I had a species that wasn’t the true Caridina multidentata all along.
Other diligent breeders have had stabs at breeding Amanos, usually involving a separate larval system rigged up with seawater, with mixed success. It’s certainly possible to do, but unless you’ve got something close to lab-grade facilities, including plankton sources, then I wouldn’t hold out too much hope for you!
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WHY NOT TRY THESE ARTICLES...
Love them or hate them, thereâ€™s certainly no escaping them; the exotic shrimps are an ineradicable part of modern day aquatics, says Nathan Hill.
With so many now in circulation — and no sign of a reprieve from the onslaught of new and unique varieties — it’s increasingly hard for the lay aquarist to tell good shrimps from bad. So, we asked Lucas Witte-Vermeulen of Sharnbrook Shrimp to introduce us to a handful of what’s available.
We had these guys in a Fluval Spec 19 aquarium for the purpose of photographing them. The first thing I noted was that looking through the open top of the tank, the shrimps took on a whole new sheen and vibrancy that seems to wane when viewed through glass.
If you are the kind of aquarist that likes to run open-topped systems, and aren’t averse to looking down from above, then you are in for a treat.
Across the board, these shrimps are impressive. We introduced them to the tank, set to a temperature of 18°C/64.4°F, and within seconds they had settled and started rummaging for food.
The varieties that Lucas brought were a mix ranging from entry level — such as Blue jellies (pictured below) — up to the true exotics such as the Royal blue tiger or Blue bolt strains. You can see more of them pictured further down the page.
It’s important to identify the shrimps as breeds rather than species because all of these variants are just that: tank bred colour types. That’s worth noting because if you’re ever told that, say, the Crystal red shrimps you’re hoping to buy are wild, then you should smell a rat.
These colourful strains are the direct result of breed manipulation rather than natural selection.
The one thing that I personally struggle to fathom is the brief lifespan of a shrimp given its often extraordinary price tag. I’m not alone in this, and the contention that comes up frequently is how anyone could part with sums of between fifty and a hundred pounds for a single animal that will at best last a couple of years.
As Lucas explained to me a large chunk of that market is for breeding, and it has to be said that these creatures are naturally inclined to being amorous. With a successful spawn or two and an ability to sell the young on, a profitable return can be enough encouragement for many.
Purchasing from Sharnbrook, the first thing you’ll note is that you get something of a 'Spanish Inquisition' moment with regards to water quality and chemistry. Before arranging to send anything out, Lucas goes to great lengths to ensure that you fully understand the exact requirements for his shrimp — in my case right down to conductivity and even substrate in the tank!
In fairness, it’s worth listening to and following what Lucas suggests. One of his claims is that despite the volume of shrimps that the company sends out all across the UK, he has yet to face a single Dead On Arrival (DOA) claim so far. For those concerned about the legitimacy of mail order livestock (at least of an invertebrate bent) this should come as something of a confidence booster, and I have already alluded to the point that our own test subjects, despite the nature of their travel, were happy and settled within seconds.
Water chemistry does need to be considered prior to purchase because these shrimps are acutely sensitive to not just poor, but also incorrect water.
Softness and acidity is the prime concern, and an ideal pH value should be somewhere between 6.2 and 6.8. Hardness needs to be low, with as little as 1°KH and no requirement for anything over 6°GH. Sticking these guys into hard, alkaline waters is a surefire way to kill them off.
Temperature is equally important, though some play is given. Even though many of these shrimps end up in tropical homes, their preference is for cooler, borderline tropical waters, and a temperature of below 24°C/75.2°F is wise.
Lucas highly recommends the use of Catappa leaves or similar, both as a generator of acid as well as a food source to encourage a degree of mesofauna and biofilm that the shrimps can graze on.
Some of the shrimps available
Royal blue tiger.
Crystal Black Bee S Grade shrimp.
Red Sakura SS Grade shrimp.
Black Taiwan Bee King Kong shrimp.
Black Sakura SS Grade shrimp.
Red tiger shrimp.
Snow white shrimp.
Crystal red bee shrimp.
Orange Sakura shrimp.
Hardcore fish enthusiasts may baulk at this, but I really like these shrimps. I’m also taken at just how explosive the proliferation of so many varieties has been. Are they worth the money? If you breed them, then definitely!
More info: Check out the website at sharnbrookshrimp.co.uk or call 0774 358 9999.
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Chris Lukhaup and Stefan Hummel find shrimp, snail and plant gems galore in three habitats of an Asian outpost thatâ€™s still simmering with internal unrest. Translation by Ulli Bauer.
The volcanic Indonesian island of Sulawesi was once inhabited by bloodthirsty pirates spreading fear among passing seafarers. Today the languages of ethnic groups there differ greatly, even though they have been living, somewhat uneasily, on the same land mass for centuries.
They have been isolated by the very geography of this octopus-shaped island once known as Celebes. It’s midway between South-East Asia and Australia and physically partitioned by steep and rugged sierras.
Between 1998 and 2006 conflicts between Christians and Muslims on Sulawesi resulted in more than 1,000 deaths. Currently, emotions have cooled and news has filtered out about some fabulous freshwater inverts there.
Numerous attractive snails have recently been discovered in the island’s Malili lake system, including some beautifully coloured and patterned shrimp. Many waterplants found there have still to take root in the hobby, though.
Naturalists Wallace and Weber have contributed greatly to the exploration of the island. They found Sulawesi to be a link between Asian and Australian flora and fauna, but most plants and animals there are endemic.
My colleagues on our expedition there were Stefan Hummel, the Logemann brothers from Hamburg and Thomas von Rintelen of the Natural History Muesum in Berlin. After a day-long journey from the provincial capital of Makassar to the northern port of Poso we immediately went invert hunting.
Small white Fiddler crabs of the Uca genus, as well as some hermit crabs, indicated a brackish habitat for the area.
We also found a group of Faunus ater snails in shallow water. These grow to a shell length of 8-9cm/3.1-3.5” and live mainly in the mouths of small to large rivers, grazing on the muddy ground. They have also been reported in heavy currents and pure freshwater, but also in brackish lentic waters — even marine conditions.
Turning with tides
When the tide was low, they moved towards the sea some 50 metres away with the freshwater from the river and returned with the flood tide.
Not much is known of their reproductive biology, but their distribution suggests larvae hatch from their eggs, needing marine conditions to grow, and they re-migrate to freshwaters when developed as snails.
We then ventured into the highlands, finally reaching the sparkling blue waters of Lake Poso and on the sandy beach immediately found shrimp and snail species where the water was a cosy 28°C/82°F.
At first glance the bottom appeared empty, but a closer look revealed Caridina ensifera (above) and Caridina longidigita shrimp, several crabs, gobies and more than one Tylomelania species of snail on the rocks and in mud.
We chartered a boat to a small, remote bay on Lake Poso’s western shore. Alone on this dream-like beach we found beautiful Caridina ensifera on rocky to pebbly ground in shallow water. When the water reached a depth of 1m/3.3’ we found groups of Caridina caerulea (pcitured above) sitting on every submerged tree trunk and branch.
This shrimp species has been introduced in the hobby as Blue Morphe. Usually these have a long blue rostrum, but their bodies are more or less transparent and only their tail fan carries two striking blue dots. However, some specimens have all-blue bodies.
In Lake Poso, they are not as common as C. ensifera, which display a similar pattern but the coloured areas are red instead.
Blue Morphe shrimp are mostly found on rocky ground, on wood or on pebbles, and sometimes on softer substrates like aquatic plants. This is the only blue species in the lake, as most of the others are reddish or brown.
We also saw yellow Tylomelania sp. snails on rocks as well as mud, but they seemed to prefer a hard substrate as their offspring were 1-2m/3.3-6.6’ down on boulders. Their dark brown to black shells show a pronounced spiralling and axial sculpturation, their bodies being bright yellow to orange.
We did not get to find any large specimens, though, as we had to return to the surface. To find adult snails you really must have proper diving equipment!
We saw C. longidigita in the crevices of rocks on the shore, constantly filtering water for food with their tiny fans.
A few kilometres and 3,500 potholes later we came to a spectacular waterfall with thick lime deposits — the home of Tylomelania sp. ‘Thunderbolt’. This river carries so much calcium oxide that its deposits cover everything. Even the mosses and tree roots in the splash zones are coated by a whiteish layer of lime.
Next morning a rented boat brought us to a rocky shore a few kilometres off the island of Ternate and home to quite a few hitherto undescribed snail species Thomas had collected in 2007.
It was windy, waves were high and filming almost impossible. We planned to return later with a small dragnet, as many of these new snail species are only 9-10m/30-33’ down.
We adjourned to a bay with shallow, calm water, covered by a carpet of floating Nymphaea indica leaves and thousands of the small, attractive flowers shimmered in the noon sun. The Indian Water Lily is, however, hardly useable in aquarium tanks as it exclusively develops floating leaves.
We circled 100m/330’ offshore where depth was around 10-15m/30-33’ and drag netted some of those new Tylomelania. One was a red and white beauty, with green eggs.
We lowered the net several times and found even more new shrimp and snails.
Next day we were scheduled to go to Lake Matano in south Sulawesi, taking a bumpy ride to a brook which seemed perfect for shrimp — but proved otherwise.
However, Stefan discovered a miniature waterfall in dense jungle en route, with beautiful mosses growing on the rocks and tree roots around it. He found a coral moss of the Riccardia genus there from the Arneuraceae family and highly prized.
Shortly before we reached Lake Matano we stopped by a river and the habitat of two new crab species. We also collected the Sulawesi Bee here — these small shrimp preferring areas with weaker currents.
Their rostrum is extremely short, looking as if it had broken off just behind the eyestalks. They live on rocky substrates and should kept as such in aquarium tanks with lots of rock structure. They mainly eat aufwuchs and will breed in captivity, although not an ‘easy’ species. The females carry more eggs than other Sulawesi shrimp.
One species, very small and similar to the Micro crab (Limnopilos nayanetri) seems to belong to a new genus hitherto unknown from Sulawesi and it is now being closely inspected.
After a five-hour drive we arrived at Nuha, a hamlet in the north of Lake Matano, where a ferry took us to the mining town of Soroako.
The lake is more than 600m/1,970’deep and home to some of the most beautiful freshwater shrimp and we found the Cardinal (Caridina dennerli), named after the Dennerle plant specialist company, at a rocky reef.
This species (pictured above) has so far only been found here, hidden among rocks of the coastal zones down to around 10m/33’. Their usual colour is red, with white dots, but some have blue dots or larger blue spots.
If they get stressed they can turn blue, but only for a few minutes. Often they are dark red in the morning, fading to light red in the evening — seemingly according to their moods.
In the aquarium, Cardinal shrimp are often shy and remain hidden in rock crevices all day, as in nature. These are best kept in a dedicated tank where their white claw feet will keep moving, grazing aufwuchs from hard surfaces.
Our next location was a small island and under leaf litter and rocks we found Caridina holthuisi, C. lanceolata, C. loehae and many Tylomelania snails. There were even Matano crabs at 2-3m/.6.6-9.9m down.
C. holthuisi (above) is found in Lakes Matano, Mahalona and Towuti, and a population is known from the Petea river, preferring to live in leaf litter or detritus, sometimes on waterplants. They are usually dark brown to black to confuse predators, but some are white or cream-coloured to blend with where they live.
C. loehae are distributed all over Lake Matano and live down to 5m/16.5, as well as in places like Lake Towuti and the Petea river.
As rock dwellers they share their habitat with C. dennerli and C. parvula. They are red or reddish brown and have white dots as well as a characteristic cream-coloured stripe across their back.
After transportation they may go purple or blue, but, after adapting, will return to their original reddish.
We rounded the island underwater amid impressive populations of Ottelia mesentherium. From the family of Frogbit (Hydrocharitaceae), this plant is endemic to Sulawesi and only found in the Malili lakes.
Ottelia grew at a depth of around 80cm-3m (32”-10’) and its crimped leaves look similar to Crinum calamistratum, originating from Africa, and and were particularly deep rooted.
The shallow water of another bay was densely overgrown with stonewort, an algae that looks much like hornwort.
Closer inspection revealed a fantastic local population of Ottelia alismoides, a perennial that reminds a bit of a waterplantain of the Alisma genus — hence the species name alismoides.
On the shore there were bizarre Pandanus bushes, among which was a large patch of Eriocaulon, and a close examination found at least four growth forms varying between 1-2cm to 6-7cm (0.4-0.8” to 2.4-2.8”).
Typically, these plants will display firm, almost throne-like leaves.
The Eriocaulon fields were interspersed with several stoneworts of the Chara genus and it’s still unclear if they can be grown in aquaria.
A special botanical surprise then revealed itself — a miniature plant of the Lymnocharus genus. Its shoots are tiny with thicker ends and plants are only a few millimetres high. Despite this, they have an enormous root system.
This sandy area on the shore was also home to carnivorous plants and in thick leaf litter in shallows we found some Caridina holthuisi.
Our last spot revealed underwater ‘scapes that reminded us of Amano creations! Here we found a great variety of Tylomelania species, Cardina shrimp and even fish of the Telmatherina genus, of which the males, shimmering in yellow or blue coloration, were performing mating dances.
The dominant plant was again Eriocaulon, along with populations of Lymnocharis. The thin stems of their floating leaves looked like fishing lines in the backlight. What incredibly mystic scenery!
Departing for Lake Towuti, we chartered another boat and at 1-2m/3.3-6.6’ saw the tiny white claw feet of freshwater Harlequin shrimp (Caridina woltereckae). They sat in rock crevices, hidden and protected. Around the rocks, several large tilapias circled. These food fish were introduced some years ago and predate heavily on shrimp.
This shrimp’s red and white striping is quite striking, even though some specimens may be less intensively coloured than others. Some are even transparent with light red stripes.
Such typical striped patterning is misleading, looking similar to C. spongicola. However, the latter are only found in one spot in the lakes and live exclusively in and on freshwater sponges. The Harlequin lives on hard substrates.
As the sponge is often found with other dwarf shrimps it may also be kept with them in aquaria. In the tank, specimens need lots of rock structures to retreat into crevices.
They do not breed easily in captivity and few specialists have succeeded. In any case, they have low numbers of offspring.
Caridina spinata are similar. Rock dwelling, they also originate from Lake Towuti and are usually found on large trunks or pieces of wood down to 3-5m/10-16.5’. Adults live in the lower areas, scavenging for food with other rock dwellers.
They have variable patterns —from a deep dark red with orange or yellow cross-stripes and dots of almost solid orange.
This species belongs to the larger groups of the lake and can be easily told part from others in the same habitat by striking colouration. Being highly susceptible to stress, they should best be kept in a dedicated tank.
However, they can be co-housed with Tylomelania snails that also live in Lake Towuti.
The scenery was beautiful on the shores of the Tominanga river, although we gulped when approaching the first rapids. It didn't help when Thomas told us his boat had keeled over in this very spot in 2004. Chins up, we went through and 20 minutes later reached Lake Mahalona.
We stopped at a shallow area and immediately went into the water. Beautiful Ottelia and Sulawesi grasses grew there, most endemic to Lake Mahalona, as were most of the Tylomelania species we found. On the shore we came across crocodile traces, so returned to the boats to explore another spot.
After a few minutes aboard we even saw a crocodile relaxed and floating on the lake!
A small rock mass offshore suggested that its sharp edges would be quite uncomfortable for the soft bellies of the crocodiles we knew inhabited these waters so, going in, we witnessed unsurpassed underwater scenery.
The plant community was again characterised by cacti-like Eriocaulon species and those small Lymnocharus, with their line-like stems and tiny white flowerlets, were also in large numbers.
On another spot on the shore we saw several Eriocaulon growing above the waterline — a hint that they might also grow emerged. During the low water season some probably grow on land for several months.
When we ventured inland a few metres we found a gorgeous population of Limnophylla aromatica, its stems growing outside the water, too. Underwater they were olive green and above a blackish red with purple flowers. L. indica is widely distributed over South-East Asia, but not often found in aquatics.
On our return we had to cross Lake Towuti again and met a shrimp collector filling already crowded containers. Our suggestions to put in less shrimp and more water fell on deaf ears!
However, he invited us to look at his storage facilities in Timampu. This hamlet on the shore of Lake Towuti is home to several shrimp collectors. Here, these shrimp start their journeys to Europe or Asia — and into our hobby.
Where we collected
Lake Poso: Temperature 27.7°C/81.9°F; pH 8.1; GH 5; KH 4; conductivity 109 µS/m; oxygen 7.05 mg/l.
Lake Matano: Temperature 28.7°C/83.7°F; pH 8.5; GH 7; KH 5; conductivity 175 µS/m; oxygen 6.93 mg/l.
Lake Towuti: Temperature 29.2°C/84.6°F; pH 8.4; GH 6; KH 4; conductivity 146 µS/m; oxygen 7.15 mg/l.
The river in which we found the Sulawesi Bee shrimp (Mambo bee) had a water temperature of 23.2°C/73.7°F; pH of 8.3; GH 12; KH 6; conductivity 289 µS/m and oxygen 7.42 mg/l.
Chris Lukhaup visits China and Hong Kong to examine and photograph the elusive and protected natural habitats of most of the shrimps we see in the trade.
Of the shrimps in the hobby, most are found in South China. Until now little was known of their biotopes and living conditions and most information was gleaned simply from aquarists’ experience. Reason enough then for the Crusta10 team of Werner Klotz, Andreas Karge and myself to head east to get a privileged insight into the natural conditions of their remote hideaways.
Bee, Bumblebee and Tiger shrimp, all widespread in the hobby, originate from the province of Guangdong (Canton) in South China where they live in headwaters of small mountain rivulets. Other species are also there but less interesting in coloration and/or pattern.
Many are only known from scientific descriptions, others are unknown and probably yet to be scientifically described.
The Crystal Red shrimp also has origins here, its ancestors living in a rivulet in Greater Hong Kong. However, you’ll look in vain for photographic evidence or for water parameters of this habitat!
With the help of Ping Yiu Tang, a fish wholesaler from China who was our interpreter and guide, we visited some small brooks, previously kept secret by insiders, to gather data with the help of his local shrimp collectors and to film the habitat.
We flew to Hong Kong and first visited Mr. Tang’s farm just over the border in China, where some 8,000 shrimp caught by his collectors are temporarily housed and prepared for export to Europe and Japan.
They are kept in large tiled concrete basins, and animals from different locations sitting together in one tank are not exceptional. This means that several species may be put into one bag, which makes identification difficult.
Next day we made a three-hour drive to the long-promised habitat. The rivulet we visited is among mountains near the city of Heyuan and belongs to the owners of the huge Xingfeng Jiang reservoir. This remote corner is also home to Caridina meridonialis, a Bumblebee shrimp only recently described.
Appeasing the god
However, the collector said that to catch shrimp we had to get the mountain god’s permission. So we climbed for one and a half hours through mixed tropical forest to offer sacrifice with candles, rice wine and fireworks on a centuries-old altar. This appeased the god and enabled us to collect shrimp!
After the ceremony we descended for about 30 minutes until reaching a small, clear rivulet in the forest where we could see black and white Bumblebee shrimp.
They were mainly in shallow areas along the bank and not shy — probably due to the fact that there are no predators, like fish or waterfowl. There were also stray colourless shrimp, which, though still unidentified, might belong to the group of C. serrata or C. cantonensis. The Bumblebees were C. meridionalis, as expected.
After filming and photographing we took some water parameter figures from the habitat. The brook was about 1m/39" wide, slow-flowing and had a temperature of 16°C/61°F. There was no detectable carbonate hardness and conductivity was only 12 µS, while the pH was only 5.8. The habitat therefore had all the typical characteristics of a softwater brook.
On the banks of the heavily shaded rivulet were interesting ferns and mosses. In the brook itself, with rocky to sandy ground, we could not find any waterplants or mosses. There were vast amounts of fallen leaves in the larger pools, though, and this is where we found most shrimp.
The next rivulet was also quite remote but easier to reach. Here we also found dwarf shrimp with black and white stripes, even though their pattern was a little different. The habitat was comparable to the first, but the riverbank plants seemed to grow more densely here.
The brook’s water parameters were even more extreme than those of the first habitat. Water temperature was the same, but conductivity was only 7 µS, as taken with our pocket conductivity meters. However, the pH of 5.4 backed this finding and indicated the lack of any hardness buffers. We did not find any acid-binding capacity (ABC, KH) with our drip tests, even with the double amount of water. We could say the shrimp here live in pure rainwater.
Driving coastwards to the border between China, Macao and Hong Kong we collected in a small brook, winding around large granite blocks in an amusement park. A few metres upstream we could see blueish-grey shrimp and Werner assumed they might belong to the genus Neocaridina, as many females had a broad stripe along their backs and looked very much like those exported from Hong Kong as Neocaridina sp.
However, Werner and Andreas later discovered that these had to belong to the group related to C. serrata and C. cantonensis. Later, at home, they corroborated this finding under the microscope.
Much to our surprise, we found another shrimp species with dark and light bands. The younger animals particularly showed a very clear black and white pattern. Some were even blue and white, and quite different from those collected at Xingfeng Jiang reservoir a few days earlier.
We later found that the blue and white as well as the black and white shrimp belong to a species of the C. serrata group, which therefore makes them a distant relative of our Bee shrimp.
It’s possible that we have now found the shrimp that Taiwanese and Japanese breeders used to create the Red bee shrimp.
We also saw professional collectors looking for shrimp in this brook. It is highly probable then that animals from this location were mixed with other species in the wholesalers' tanks and so made their way into the hobby.
Nearly always working in full sun we were able to find shrimp in this habitat in nooks and crannies of granite rocks where they were searching for food on the sandy to rocky bottom. They were well camouflaged by their pattern and much more shy than their congeners in the forest rivulets. One reason might be because of the fish we detected in this brook.
However, the banded shrimp were less common than the uniformly greyish-blue ones. With the brook in full sun, without any riverbank forest for protection, water temperature was 22°C/72°F and significantly higher than the rivulets. However, the water was very soft, conductivity was 32 µS and we could not detect any KH. The pH was 6.0.
After our experience in China, the Hong Kong habitats seemed a lot easier to find. Shrimp are even said to live in the small park brooks within the city itself.
Four species are currently known from there: C. serrata, C. trifasciata, C. cantonensis and C. apodosis — and all belong to the group of C. serrata.
When the shrimp hobby started to boom, Bees were named Caridina serrata as it was then unknown that they might belong to a completely new species. The true C. serrata (above) is transparent to greyish or reddish brown, has irregular dark lateral bands and looks totally different to the black and white banded Bee shrimp.
It’s highly unlikely that these shrimp have already made it into the hobby. The species is endemic on Hong Kong island where it lives in small mountain brooks carrying water year round. You can find large numbers, often where a lot of dead leaves have accumulated.
Water temperatures of these brooks were quite coolish at 18-19°C/64-66°F. A small, slow-flowing rivulet had a low conductivity of 80 µS and a pH of just under 6. Here we also found other inverts like Brotia hainanensis (above) a snail species common in Hong Kong, and a hitherto unidentified crab species.
In the estuaries in the east of the New Territories we stopped by a small river in the tidal zone that had little water at this time of day. We caught a Caridina species under some rocks that science has labelled C. elongopoda, which, however, shows clear differences compared with the true C. elongopoda from Malaysia, according to Klotz and Karge. A more thorough examination might be necessary to place these animals in the right species.
We were also able to catch several Macrobrachium and a Palaemon shrimp species. We also collected nerite snails of the genus Clithon on the algae-covered rocks. These snails are variable in colour and vast numbers of their egg cocoons were the rocks. The banks were strewn with crab caves, but we did not see any crabs.
The water in this area, about 500m/1,640’ from the estuary, was slightly brackish with a conductivity of 1,120 µS, at a temperature of 19°C/66°F and slightly acidic pH of 6.8.
When following this brook up to the mountainous forest area the conditions changed. The water body was heavily shaded, slow-flowing and there were masses of dead leaves on the bottom.
Here we found Caridina cantonensis, the most common species on Hong Kong island. Some are reddish yellow, some rather blueish with a red-brown dotted pattern. The higher you climb, the stronger the current, the steeper the rivulet’s gradient, the more shrimp can be found. They look very much like Red tail shrimp already in the hobby.
These shrimp shared their habitat with some Brotia hainanensis and a Macrobrachium longarm shrimp not yet identified. There were also fish in these waters, among them a loach species identified as Liniparhomaloptera disparis and a small goby with a bright orange dorsal fin from the genus Rhinogobius. The water up there was around 2°C cooler than in the brackish area, pH was 6.4, and there was no detectable KH.
Next day we went to the eastern part of the New Territories where Tang wanted to show us a rivulet where he used to collect shrimp and where Caridina as well as a Macrobrachium species could be found.
Hands as food
When we reached the brook, the longarm shrimp’s behaviour astonished us all. They were far from shy and if you held your hand in the water they literally swam towards it to see if it was good to eat. These belong to the species of Macrobrachium hainanense.
There seemed very little food in the brook, there being no other explanation for this excitable behaviour. Moreover, we could not detect any larger fish there that might pose a danger to them.
The dwarf shrimp population is very small here, the longarm probably predating on them — which would explain this remarkable phenomenon.
We followed the rivulet, which ran through rainforests with abundant vegetation as well as open landscape, upstream. On a small plateau where the brook had carved into the rock we found some smaller fish species in larger pools and many Caridina cantonensis in those pools that had large amounts of fallen leaves.
We found it astonishing that the dwarf shrimp were not in the pools with algae and mosses, but in those with rocky bottoms and lots of detritus. Parameters were pretty much like those we had taken so often during the previous days: temperatures around 18-19°C/64-66°F, conductivity between 45-48 µS, and pH values correspondingly between 6.0-6.4.
One secret too many...
Could we actually get to see the original Bee shrimp habitat? The Holy Grail itself?
Mr. Tang had helped make the arrangements for the last day of our trip, but it ultimately proved impossible as if collectors learned he had shown their top secret location to strangers they would poison the entire brook — as they are reported to have done before.
In order to protect their interests, the professional collectors of Hong Kong seem to stop at nothing.
This item first appeared in the January 2010 issue of Practical Fishkeeping magazine. It may not be reproduced without written permission.
Freshwater shrimps have never been more popular. Ade Dunn explains how to keep and breed those of the Neocaridina genus.
A genus of dwarf freshwater shrimp, Neocaridina include varieties such as Cherry shrimp (Neocaridina heteropoda var ‘red’), Snowball shrimp (Neocaridina cf. zhangjiajiensis var 'white'), Blue pearl shrimp (Neocaridina cf. zhangjiajiensis var ‘blue’) and also Yellow shrimp (Neocaridina heteropoda var ‘yellow’.
Some of the best for beginners belong to this genus, such as the Cherry. Most are hardy and comparatively easy to keep.
Where do they come from?
Wild Neocaridina shrimp mostly originate from South-East Asia, living in streams and ponds, usually with plenty of plants and often with wood and rocks as natural substrate. Many species in the hobby, however, have been captive bred and, in some cases, the original wild species is debated.
How are they best kept in the aquarium?
Neocaridina are usually best kept in well-planted aquariums, with plenty of hiding places and mosses. I find they also do well when kept with bogwood, and stones. Plants and décor provide hiding places and a surface for bacteria and other tiny organisms, including algae, to live on. These are pretty much an essential part of shrimp diet.
I prefer to keep them in groups of at least six, as in smaller numbers they can become shy. A large group also increases the gene pool.
Is there a minimum tank size?
Neocaridina shrimp have very small bodies and usually add little to the bioload of an aquarium, especially when kept with other tank mates and not target fed. However, when kept in species tanks they have more impact as they need to be target fed rather than take leftovers.
However, they can still be kept in very small tanks if well planted and with adequate filtration, so are popular in nano and pico aquariums as small as 15 l/3.3 gal. Anything less is not really suitable, as six neocaridina can quickly become 100 in a short time!
This said, the bigger the better. Use the largest aquarium you can fit in and afford. A larger volume of water will give you a larger ‘safe’ zone, especially where temperature and water quality are concerned. One often fatal factor is sudden temperature increases, or changes in water quality, and smaller bodies of water are far more prone to sudden changes.
What sort of water conditions do they need?
Any dwarf shrimp needs high water quality. Even a tiny trace of ammonia is fatal and these creatures are also intolerant of nitrite. As such they should only be stocked in well established aquariums with fully ‘cycled’ filtration.
Too much copper is also fatal. You cannot use medications containing traces and new plants should always be soaked and rinsed thoroughly to remove any traces of copper-based anti-snail treatments.
However tiny trace amounts of copper, as found in many aquarium plant fertilisers and foods, are usually harmless, unless you already have another source of trace amounts of copper. There may be fairly high levels in your tapwater, or you could overdose these above recommended levels.
In fact, some shrimp food manufacturers add trace amounts of copper as shrimp need these to produce the oxygen-carrying component of their blood in a similar way to how we need some iron for ours. In excess, however, this is harmful to humans.
Most species of Neocaridina do best in medium to hard water, with a pH of 6.5-8.0. Where water is soft, however, calcium supplements may be needed to help the shrimp during moulting when calcium is needed to help make new 'skins'.
As to temperature, most will tolerate as low as 18°C/64°F. They will tolerate even lower for short periods, making them quite easy to ship, and accept as high as 28°C/82°F. However, I find they live longest and breed best between 21-26°C/70-79°F.
At higher temperatures growth and breeding might be faster, but their life spans are considerably shorter due to the increase in their metabolic rate cause by those temperatures. In warmer water you may also need to add additional agitation/aeration to compensate for the lower amounts of dissolved oxygen.
What fish can they be kept with?
I tend to keep my dwarf shrimp with just snails and other dwarf shrimp. This way you will see more of your shrimp and more of their natural behaviour, such as swimming to the surface and hanging from floating plants.
However, if you want to keep fish choose those too small to make a meal of your shrimp, including the young if you want to breed them. Choose also primarily plant/algae eaters, but remember that few fish are 100% vegetarian and most will take a meaty morsel if presented.
Those fish also need mouths too small to easily bite a shrimp — which must also have plenty of hiding places available in which to retreat when moulting. At that time their soft bodies make them an easy target, even for smaller fish.
Among the safest bets to keep with dwarf shrimp are probably small varieties of Otocinclus catfish which are usually considered 100% shrimp safe, even with newborns. Other species that may be safe are smaller Corydoras species and small loricariid catfish such as plecs which stay quite small.
I have also kept shrimp with dwarf gouramis, smaller tetra species, smaller Rasbora species, Cherry barbs and Kuhli loaches, but this was in a densely planted aquarium where shrimp can hide easily but be rarely seen.
Won’t they be sucked into my filter?
This is a common problem with internal or external power filters, especially for babies. However, it can easily be solved. Either push fine pored foam over the inlet — useful for intakes of canister filters or hang-on types that have intake tubes — or cut out the foot of a fine low-denier stocking and fasten it over the intake of your filter with an elastic band.
If the suction from your filter is still strong enough to suck on shrimp and keep them there, either turn the flow down, if there’s some control, pack your filter with more wool to reduce flow — or, in the case of internal power filters, put a thick layer of filter floss between the body of the filter and the stocking foot fastened over it.
If you have an external canister filter, don’t panic if shrimp get sucked in. I often find colonies of Cherry shrimp happily living in my filter, feeding on the bacteria growing on the media and safely away from the fish. As long as they can’t get sucked into the impeller they should be OK
Alternatively use some form of air powered filtration, the most popular forms being an air-driven sponge filter or a make-your-own Hamburg Mat Filter. This basically consists of closing off a corner of your tank with a flat piece of fine pored foam and using some form of water pump or air lift to pull water across/through the foam before been returned to the main part of the aquarium.
How do they breed?
No special steps are needed to get neocaridina to breed. if you can keep them alive and healthy they will breed.
Neocaridina dwarf shrimp usually spawn shortly after moulting, the female releasing pheromones into the water to indicate her readiness and exciting the males. A good sign with most species of Neocaridina that the female is approaching readiness is seeing a coloured area form at about 'shoulder' height. This comprises the immature eggs visible through the shrimp and usually called a saddle by shrimp keepers.
Dwarf shrimp mating takes place with the shrimp facing each other, the male putting his sperm on her genital opening.
As the eggs pass through this opening they are fertilised by the sperm and then placed along the female’s abdomen among her swimming legs (pleopods) where she will carry them until ready to hatch after about three weeks to a month.
How do you raise offspring?
Neocaridina shrimp show no parental care and babies are very vulnerable, being only a millimetre or so in size. If kept with fish it is very important to provide mosses and other places in which they can hide and feed.
Offspring must be kept in a mature aquarium. A newer one will not contain enough minute organisms on which young shrimp primarily feed and is a common reason why breeding attempts fail. As they grow the young will eat particles that break free of shrimp foods and will also graze on any algae.
Water quality should continue to be maintained, as should the temperature of their aquarium.
Which species are easiest to keep?
All Neocaridina are easy to keep. The easiest are probably wild type Cherry shrimp (Neocaridina heteropoda) and Neocaridina palmata. However Snowball and Blue pearl shrimp are fairly easy and breed but can be more sensitive due to the inbreeding needed to fix their colour forms.
Why do they sometimes die for no reason?
The simple answer is that they don’t — we just don’t understand or find the reason why. There are, however, a few possibilities to consider if you have 'unexplained' deaths:
Old age: Neocaridina shrimp rarely live longer than 12 to 18 months, so if you buy full grown shrimp they may already be getting old.
Copper poisoning: Have you changed your plant fertiliser or dosing regime? Perhaps you have added new plants, or used water from the hot tap during a water change? Did your shrimp show signs of lethargy before dying?
Failed moulting: This is all too common, with shrimp starting to moult and then appearing to drop dead for no reason. Possible causes can be a lack of calcium or iodine in diet, so if this happens a lot consider adding foods containing these. Most crustacean and shrimp foods contain additional iodine and calcium, often in the form of seaweed for iodine.
Too high CO2 levels/not enough dissolved oxygen: Before they died, did your shrimp appear to spend much time near the surface or 'surfing' in the flow from your filter outlet? If so, consider increasing surface agitation/aeration, or if using pressurised CO2 check your gas levels. If too high, reduce how much you are injecting.
Reduction in water quality: Have you recently added more stock or cleaned out your filter? If so check your nitrite and ammonia levels as a small ammonia spike may have occurred and killed your shrimp.
Predation: If in with fish or larger predatory shrimp they may have fallen victim to predation or harassment. Being 'messed with' by bullying fish can lead to death.
Disease: Little is known and without microscopic examination a disease can be difficult to spot. As a general rule, however, if your shrimp are kept in good conditions you will rarely encounter any ailments.
This item first appeared in the July 2009 issue of Practical Fishkeeping magazine. It may not be reproduced without written permission.
Fiddler crabs strike the right chord for Frank Schaefer who explains thereâ€™s more to these creatures than just highly individual performances.
There are some 100 species or sub-species of the Uca genus, but determining them is often difficult as specific features described in scientific literature are often useless without comparative preserved material of other species.
These fiddler crabs — on sale as Uca sp. 'Haribo' — are an import from Indonesia. It is claimed to be a single variable species and might belong to Uca crassipes, a species with a fairly wide distribution in the Indo-West Pacific, but as long as this is uncertain it seems wise to use only a popular name - it may actually be a collection of species.
There are two explantions for the general name of fiddler crab. Both refer to the feature among males which have one enlarged claw.
Some say they are called fiddlers because their large claw looks like a fiddle. Others believe the 'waving' of the claw resembles the movement of a bow over fiddle strings. This latter explanation seems more substantial.
The enlarged claw can be on either side, differing individually and is not species specific. Rarely, and mostly in bred specimens, both claws are enlarged. Such claws are used by the males to perform courtship and for ritualised fights.
The second, normal, claw picks up food, while both claws on females are normally developed. All fiddlers, however, prefer to pick relatively small food particles.
In nature, they can be found in a wide variety of habitats. Many live on sandy beaches, some in muddy mangroves, others on rocky shores.
Three or four species can often be found living syntopically. Although this clearly shows that the different species inhabit different micro-habitats and obviously have different food preferences, all can be fed in captivity with artificial fish food tablets. These fall in pieces when in contact with water and are readly taken by the fiddlers. Many other types of food are also taken.
These crabs can refuse all food, usually due to transportation damages and/or diseases.
Dead leaves of oak or beech should always be in a fiddler crab tank. These creatures feed on them and on detritus from the leaves. Avoid pellets produced for food fish, however, as their high protein content could lead to fatal nitrite levels in the water.
All fiddler crabs are more or less euryhaline because they have an amphibic way of live. During high tide they hide, flooded in self-burrowed holes, and leave them during the ebb to feed and mate. They do virtually everything on land.
During heavy rains they can find themselves in pure fresh water. When a big wave breaks they can be washed into saltwater again. However, keep them in aqua-terraria with strong brackish or pure marine water.
A tank for fiddlers, like the Haribo, need not to be big. This species (or these, if actually several) stays relatively small, the carapace width hardly reaching 3-4cm/1.2-1.6“. For three or four males and an equal number of females a tank of 60 x 30 x 30cm/24 x 12 x 12“ is big enough, but larger tanks are easier to keep stable in respect to water quality.
It is not necessary to imitate the tides. The fiddler tank should have a large land mass of fine sand and a smaller section of water at an area ratio of 2:1. The water level should not be higher than 5cm/2“.
The beach should be stabilised with stones or glass, otherwise the sand will slip in the water. Install good aeration in the water section too, preferably using an air tube. The sand will work like a big bio-filter if there’s strong enough water movement through the air bubbles. If there’s insufficient movement the sand will become foul and smelly.
Such a situation is dangerous. Evaporation is relatively high in these tanks, so control salt content regularly. Mark the water level on the glass. When water has to be filled up only use pure fresh water as the salt does not evaporate! There is no danger to crabs if salt content fluctuates slightly, as they are used to it in nature.
In such a small tank Haribos should be kept alone. However, if you have a larger tank, some interesting species are available and suitable and have similar needs. These include the Zebra snail (Neritina turrita), the brackish water Hermit (Clibanarius africanus) and dwarf mudskipper (Periophthalmus novemradiatus). You can also cultivate small mangrove seedlings in larger tanks.
It is possible to breed fiddler crabs in captivity, but there are no reports about success with Haribos yet as the first imports appeared only in January this year.
All fiddler crabs reproduce in a similar way. Females carry the eggs under their abdomen. When they are ripe the female enters the water where all larvae hatch immediately. These are called zoea and resemble water fleas. They are free swimmers and eat rotifers and freshly hatched brineshrimp nauplii.
After three or four moultings into other states of zoea they moult into the final larva state called megalopa and these look like a crayfish. They are still free swimming but tend to settle and, after a final moult, the young look like the adults and start the typical way of life of fiddler crabs. Rearing larvae is only possible in marine water.
For other crabs, see the following:
This item first appeared in the June 2009 issue of Practical Fishkeeping. It may not be reproduced without written permission.
The Tylomelania snails are beautiful, inquisitive, lively and adaptable â€” in fact almost everything you donâ€™t generally associate with aquarium snails. Chris Lukhaup explains why they are truly exceptional.
The Tylomelania snails from Sulawesi surprise us all with their colours, patterns and forms. Their size is another factor that makes them without equal in our aquariums. Those colours range from orange to gold-dotted and they proudly show them off if left in relative peace.
During the last few years, the genus Brotia, with their well-known representative, the Brotia pagodula, was a sensation in aquatics. However, it was soon discovered that most imported species do not do well in captivity.
Yet the Sulawesi snails do. If kept at suitable temperatures of 27-30°C/81-86°F, they are the largest imported water snail compatible with tank keeping. They even reproduce in the aquarium.
Their appearance is very variable, but always stunning. There are many varieties, from relatively smooth shell structures to heavily-sculptured long, conical shells. Most species have not been scientifically described so far, but many are already offered in the trade.
The shells grow to 2cm-12cm/0.8-4.7“ in length, so some could rightfully be called gigantic. Their apices are almost always corroded. They all have a trap door (operculum) with a central nucleolus surrounded by five to 11 rings. However, the operculum is too small to close off the shell entirely.
The bodies and feet display truly a feast of colour. Some have black bodies strewn with white or yellow dots. Some are monochrome, yellow or orange, or pitch black with yellow tentacles — but all of them look truly stunning.
Their eyes, at the bases of the straight, thin tentacles, are clearly set off against the long, soft, almost cuddly snout.
There is a clearly visible groove, starting in the shell and running over the body and foot, within which the eggs are transported to the outside when they are released.
Range and habitat
Sulawesi (formerly Celebes) near Borneo has an uncommon form. Due to this and its location the island has different climatic zones. The height of the rainy season lasts from late November to March. The mountain ranges, up to 3,500m/11,400’, are mostly covered with tropical forests. Narrow flatlands are close to the coasts.
The height of the dry season is July/August. In the lowlands and on the coasts temperatures are always between 28-32°C/82-90°F. During the wet season, temperatures fall by about two degrees Celsius.
In the Lake Malili system, Lake Poso and their affluents, Tylomelania snails are found on hard as well as soft substrates. The largest population densities have been observed in depths of 1-2m/3.2-6.6’ and their numbers decrease sharply in deeper regions.
On Sulawesi, at the species locations of the snails imported to Europe, temperatures between 26-30°C/79-86°F prevail all year round and the water is similarly warm. Temperatures of 27°C/81°F are still measured at a depth of 20m/66’ in Lake Matano.
The snails described here originate from Lake Poso and the Lake Malili system. Poso is situated at 500m/1,640’ and Matano at 400m/1,312’. Both are in Central Sulawesi. The water is soft and the pH values are between 7.5 (Poso) and 8.5 (Matano).
To provide the snails with appropriate water parameters, the hobbyist snailkeeper should make sure the water is soft and pH high. However, some enthusiasts keep them in medium hard water, although it is not yet known whether this shortens their lifespan or not.
What to feed
Shortly after being introduced into the aquarium and adapting to water parameters, the Tylomelania snails start looking for food. They are not picky eaters and accept additional food.
They eat Spirulina powder, herbivore food, food tablets with a high percentage of animal proteins, and vegetables like cucumbers, bell peppers and courgettes.
Snails originally living on hard substrates will accept vegetables sooner than the others and also like to chew on intact aquatic plants.
When actively looking for food they dig into the ground and hard substrate-dwelling snails will rest on filter mats and decoration placed in the tank.
Of course, we‘d like these snails to reproduce and they have proved to be able to do so in captivity.
As front-gilled snails they are dioecious, the male fecundating the female by passing a spermatophore. This is a lump of spermatozoa held together by cement liquids produced by glandular appendages of the sexual organs.
The offspring grow in eggs in the mother’s brood pouch; each embryo lying in its own section and feeding on the nourishing substance there.
When the embryo‘s development is sufficiently advanced it is transported to the outside from under the mother snail‘s shell lip in a white-ish egg. Within a few seconds the white substance covering the juvenile dissolves and a fully developed youngster emerges.
The egg is transported to the outside in a groove in the mother snail‘s right side. Depending on the species, the juvenile snail is 0.28-1.75cm/0.1-0.7“ long.
When the snail has recently been introduced to an aquarium, so-called shock births happen frequently, possibly caused by differences in the water parameters — so snailkeepers are able to watch these births live shortly after putting the snail into their tanks.
The juveniles born inside their eggs are often a little smaller than usual. However, they can survive — but under normal circumstances they would just have remained inside the mother snail‘s brood pouch a little longer.
Generally, larger species release larger and less juveniles than the smaller Tylomelania.
These snails do not produce a massive population, as they usually release just one young at a time at intervals, and these juveniles need a long time to grow from only a few millimetres to a respectable size.
After being slowly introduced into the tank, these snails regain their activity pretty soon and go discovering. Only older adults remain in one place for a few days before they start to wander and they don’t change this behaviour pattern later on.
Only when powdered food is fed do they start crawling actively around in order to ingest it!
Many snailkeepers are disappointed with this sedate behaviour. However, if you adapt feeding habits and start giving powdered food several times a day as well as vegetables, you will observe the adults coming out of their shells, too.
For almost all Tylomelania snails taken from nature it soon becomes clear that they do not like their tanks too bright. Sure signs of excessive light are if the snails are jumpy and retreat to darker corners. If you offer them hideaways, in the form of crevices or dense foliage, they will make use of them.
Juveniles hatched in the aquarium are not secretive. They soon get used to the light and crawl freely through the tank. They are agile and eagerly go exploring — going everywhere, regardless whether hard-substrate or soft-substrate dwellers.
However, juvenile snails living on hard substrates can also be found on rocks, plants and wood and so enable us to see them more often.
When stocking a Tylomelania tank, be careful which animals you combine. There are hybrids in nature and different species have been proven to crossbreed in the aquarium, too.
Whether these crossbreeds are fertile is still uncertain. If a true-breeding strain is important, you should refrain from socialising several Tylomelania species.
Most Tylomelania species do well in a 60 or 80cm/24 or 31“ long tank. It should be clear to every snailkeeper that a species that can grow to 11cm/ 4.3“ rather belongs in a 80cm/31” tank, whereas those that reach a maximum 3-4cm/1.2-1.6“ can be kept in a smaller one.
Temperatures should be between 27-30°C/81-86°F and seasonal fluctuations might be sensible.
The snails also need enough room to move, so extremely dense vegetation is rather counterproductive.
Generally Tylomelania snails do well in the company of dwarf shrimp, small catfish and unobtrusive fish. It is important not to co-house them with any large populations of food competitors, so enabling them to find enough at all times.
Substrate should consist of mud, loam or fine sand and having larger rocks is recommended so that snails living on soft substrate as well as those hard substrate dwellers always find what they require.
A good tank decoration should include stacks of stone slabs creating shadows into which the snails can retreat, as they like to do.
These snails are best kept in a dedicated tank, possibly together with some Sulawesi shrimp, for which the water parameters are also appropriate.
An overstocked tank will take all the joy out of watching these beautiful snails, so gather all the necessary information on which snail you want beforehand and house it according to its requirements.
Don’t forget that the amount of food these snails need bears no relationship to what is eaten by those we usually kept in our tanks — Bladder snail, Trumpet snail and so on. They must get extra food, even in community tanks.
These are from an enchanting genus truly coming into their own when kept in a low-stocked tank. For a technical reference, if looking for details on these snails you’ll need to know their taxonomy, note the class is Caeogastropoda; order is Cerithioidea; family is Pachychilidae, and the genus Tylomelania.
To Thomas von Rintelen, of the Humboldt University of Berlin, who has provided me with an insight into these snails and made text documents of the respective scientific works available.
This article was first published in the March 2009 issue of Practical Fishkeeping magazine. It may not be reproduced without written permission.
Freshwater shrimp expert Chris Lukhaup explains how to keep the stunning new freshwater shrimps being exported from the Indonesian island of Sulawesi.
In the central highlands of the Indonesian island Sulawesi, formerly Celebes, the ancient systems of Lake Poso and the Malili lakes harbour two independent and endemic species flocks of the freshwater shrimp Caridina.
These are part of a well known genus in aquatics, but less well known, until now, were the flamboyant colour patterns in some species that resemble marine rather than typical freshwater shrimps.
However, these colourful shrimps are exclusive freshwater dwellers and occur only in those lake systems. They all have rather large eggs and their larvae only develop in freshwater " in contrast to other Caridina species with some salinity tolerance at the larval stage.
The fauna of Lake Poso and the so called Malili lakes, or Malili lake system, was first studied by Swiss naturalists and cousins Fritz and Paul Sarasin in 1895 (Lake Poso) and 1896 (Malili lakes). Apart from shrimps, the lakes are also home to several other endemic and partly colourful species; for example fish, snails, crabs or snakes.
An international team of researchers is describing the species diversity and trying to understand how it could evolve.
Lake Poso shrimps
Lake Poso is a solitary lake with adjacent rivers and a maximum depth of 450m/1,476 . It has very low nutrient and organic content, or, in other words, it is oligotrophic.
Four shrimp species are currently described from the lake and its river system and are Caridina acutirostris, C. ensifera (the original 'red' form is pictured above), C. longidigita and C. sarasinorum " mainly by E Schenkel in 1902 based on the Sarasins collection and revised by Cai and Wowor in 2006.
Two more are currently described by Kristina von Rintelen, Germany, and collaborators. One of the new species is still known as Caridina ensifera, but recent anatomical and genetic analyses revealed the existence of two species with two distinct colour patterns of red and blue (compare von Rintelen, K von Rintelen, T and M Glaubrecht, (2007).
Red is the original C. ensifera described by Schenkel, 1902, and blue will be described as a new species. Both are difficult to distinguish if present as the alcohol-bleached material commonly found in scientific collections, although living specimens (adults and juveniles) can always be told apart.
Besides conspicuous blueish body appendages with an otherwise transparent body in blue versus not blueish in red, the main difference is prominent in the tail fan.
Blue has an elongated blue patch on the distal part of each endopod as an upside down V-shape, whereas red has a smaller red spot on the distal part of each exopod.
Both species are abundant in the lake itself but absent from the rivers, whereas, for example, C. acutirostris, not featured here, is a typical riverine species absent from the lake.
They not only differ in colour, but also in ecological preferences and behaviour.
Blue is rather stationary and mainly found on hard substrate (wood and rocks), whereas red is often found in pelagic swarms or sporadic on various kinds of soft and hard substrate: for example, sand, macrophytes and rocks.
The latter also has the highest density of all shrimps in the lake and is often caught by local fishermen.
Shrimps from Malili
The Malili system comprises five lakes sharing a common drainage. The three major ones are Towuti, Matano and Mahalona with two small satellite lakes, Masapi and Lontoa or Wawontoa.
At approximately. 590m/1,935 Lake Matano is the eighth deepest lake worldwide. Canadian scientists measured its temperature at 27-29C/81-84F at the surface and around 27C/81F at 560m/1837 , a pH of 7.4 and a conductivity of 224 S that also did not change with depth.
Two of the Malili lakes, Matano and Towuti, and Lake Poso are known to be oligotrophic, although the three smaller lakes of Mahalona, Masapi and Lontoa are more shallow and probably have a higher nutrient content, and provide very similar ecological properties for its inhabitants.
The majority of the Malili shrimps were first collected in 1932 by R Woltereck and later described in 1937 by his daughter E Woltereck with eight species (Caridina lingkonae, C. lanceolata, pictured above, C. loehae, C. masapi, C. opaensis, C. tenuirostris, C. towutensis and C. spinata), followed by the description of C. spongicola, (Zitzler and Cai, 2006).
Currently Woltereck s species are revised and several new species are added by Kristina von Rintelen and Yixiong Cai from Singapore. Neither Schenkel nor Woltereck knew about the spectacular colours of their shrimps so unusual for the genus Caridina, although some colourful species have been sporadically described, for example C. trifasciata from Hong Kong.
All Malili species exclusively occur in the lake system, including its drainage, but some are widely distributed within the whole system. Others only occur in one or two of the lakes, or only in rivers. The lakes provide a number of micro-habitats with different substrates (soft like sand or plants, hard like rocks or wood), and the majority of shrimp species are specialised to one substrate.
Their detailed food compounds remain unknown, but in the gut of some specimens several diatoms were found, although they might also consume detritus and algae.
Not all species are specialised. Some are generalists that often occur on different types of substrate and usually widely distributed within the Malili lake system.
Their choice of habitat is rather unspecific and they can occur on soft substrate (water plants, leaf litter) or hard substrate (wood, rocks).
These are for example Caridina lanceolata, C. masapi and C. sp., a still undescribed riverine species (pictured above).
While the latter only occurs in rivers surrounding the lakes, C. lanceolata and C. masapi mainly be seen in the lakes themselves.
C. masapi has the widest distribution of all shrimps, being the only one living in the small satellite lakes of Masapi and Lontoa, but also occurring in the other three lakes and in rivers.
C. lanceolata can mainly be found in the three major lakes Towuti, Matano and Mahalona and their connecting rivers such as the Tominanga or Petea.
All generalists have a less spectacular coloration than the other more specialised species; from a reddish-translucent pattern in C. lanceolata to brownish with lighter stripes in the other species.
More conspicuous are the colourful species usually not widely distributed within the Malili lake system, but rather occurring locally restricted and highly specialised.
One extreme example is C. spongicola which is associated with a yet undescribed freshwater sponge and whose occurrence is limited to those areas where the sponge grows.
Some other examples are described here. Colour patterns are species specific, their intensity however can change depending on food supply (substrate) and water conditions " for example, some red species were observed to turn blue under stress.
Typical rock dwellers
There are a number of rock-dwelling species from Lake Towuti, the largest and southernmost of the Malili lakes, for example the beautiful C. spinata (pictured above), C. loehae and three other yet undescribed Caridina sp. C. lohae is mainly red with some white stripes or dots, C. spinata is rather dark red, sometimes almost purple with yellow or orange stripes.
The first C. sp. shows characteristic red and white longitudinal stripes with conspicuous white front legs (cheliped), the second a rather brown and white pattern of horizontal stripes. The colour pattern of the third closely resembles that of the sponge dweller C. spongicola, although it is a different species with specific substrate preferences.
These three undescribed species often occur together with C. loehae on gravel or smaller rocks in shallow water or with C. spinata between boulders in deeper water below 5m/.16 .
Another beautiful rock dwelling shrimp from Lake Matano is an also undescribed species that has a dark red body with white dots and white body appendages.
Life under leaves
One lake species lives mainly under dead leaves, although it can ocasionally be found on other kinds of substrate.
It is mostly dark brown, sometimes almost black body coloration with lighter stripes optimally adjusted to the mainly dark brown colour of leaf litter in the lakes.
This species behaviour seems to be able to adjust for, when disturbed, it usually lets itself fall downwards instead of moving in other directions.
Swarming typeIn the Malili system, depending on time of day, two species were observed in larger swarms, similar to the red C. ensifera from Lake Poso.
One is C. lanceolata, the other C. lingkonae, whose inconspicuous reddish coloration resembles that of C. lanceolata, but which can also be characterised as a specialised pelagic species.
It often occurs in huge swarms mainly in Lake Towuti, but one specimen was also found in the smaller Lake Mahalona. More details about the life history of C. lingkonae are unknown.
The colour pattern of this as yet undescribed Caridina shrimp closely resembles that of the sponge-dwelling C. spongicola.
Sulawesi lake fauna
The shrimps colour diversity is only one aspect of the fascinating fauna of Sulawesi's ancient lakes.
These are also home to many rare and unusual species, for example the shrimp sponge association that make it similarly worthy of protection as the Galpagos Islands.
Some of the highly specialised and locally restricted species with very small populations, especially the colourful ones, are already threatened with extinction by illegal logging around the lakes and other human impacts.
So, sampling living specimens should be sensibly limited to preserve the species and colour diversity for future generations.
For more information on Sulawesi shrimps check out the article: Eight new shrimps described from Sulawesi.
This article was first published in the July 2008 issue of Practical Fishkeeping magazine. It may not be reproduced without written permission.
Chris Lukhaup takes a look at the new Panda, King Kong and Red ruby shrimps taking the world of freshwater invertebrates by a cash-fuelled storm.
The first freshwater shrimps appeared in tanks around the world some years ago, triggering a new and dynamic trend. Freshwater invertebrates like crayfish, snails, crabs and, first and foremost, shrimp have since simply stolen fishkeepers’ hearts.
The uncrowned queen of this trend, the hitherto scientifically unidentified Crystal Red shrimp, is denominated for the time being as Caridina cf. cantonensis. However, there are reasons to believe that it could be a still undescribed species.
The nominate form of this shrimp originates from the New Territories, Hong Kong, but the exact location is only known to very few people — the reason for this being to preserve the economic interests of local collectors not keen on any competitors collecting and shipping these shrimp all over the world.
Meanwhile, a thriving cult has surrounded this species — and is comparable to that for guppies. There are books dedicated to the Crystal Red, shops selling exclusive CRS breeds and many web pages devoted exclusively to these wonderful animals. Breeders and hobbyists throughout South-East Asia, Japan and Europe, pay exorbitant prices for their coveted shrimp — especially if these belong to new forms or varieties.
Be it the outstanding Red Bee from Japan, Black Tiger from Germany or King Kong Bees from Taiwan, all are now ‘must haves’ for many breeders willing to meet any price for such specimens.
As an example, Red Bee shrimp are divided into different quality levels and high-bred specimens have been known to reach astronomical prices, up to 9,000 euros/£8,300 for a single one.
Most fishkeepers face an agonising dilemma when deciding to buy either one shrimp or a compact car!
Of course, you could always buy shrimp, hope to get a large number of offspring and make some serious real money with these animals. But don’t count your chickens — or shrimp — before they hatch as these have some rather high requirements and often die tragically after a few days.
New keepers will then not only mourn the shrimp offspring they had counted on but the money they had invested in the first place. Here, the common mistake on the part of many fishkeepers had been to be impatient and not cater properly to their needs.
New colour morphs originating from Taiwan are causing plenty of excitement. Their breeders call them Panda Bees, King Kong, Blue Bolt (above) Red Ruby or Golden (below). When the first examples came to Japan and Europe there was an uproar in the respective forums and among breeders — comparable to the hype around Sulawesi shrimp not too long ago.
The new morphs have been created by a spontaneous mutation first ocurring in Taiwan in the tanks of a breeder who concentrates on the very variable Red Bee shrimp. Similar mutations appeared in Germany, but none so far have brought about such an attractive outcome.
So the arrival of the new Taiwan Bees might be due to pure luck or maybe the aptitude of their breeder. By now he has succeeded in building a stable and solid strain with these variants, so has been able to lay the basis for a new generation of Red Bee.
When comparing the requirements of different shrimp varieties and forms, you will soon find they are practically identical. Some species are less complicated than others, however, and do fine at high pH values or in hard water. However, if you want to breed them successfully you will always have to provide water parameters similar to the conditions of their habitats in South China, Taiwan or Hong Kong.
When Andreas Karge, Werner Klotz and myself went to these habitats in South China and Hong Kong last year we found these waters have all quite similar water parameters.
The shrimp live mainly in shallow water near the riparian zone of the small, slow flowing brooks whose temperature was rather cool, measurnig only 16°C/61°F. There was no carbonate hardness to be detected and the electrical conductivity was 12 µS, which results in a pH of only 5.8.
Their habitat had all the characteristics of a typical softwater rivulet.
On the banks of the heavily shaded brooks there were interesting ferns and mosses, but we couldn’t detect any plant growth in the water. The bottom substrate varied from rocky to sandy and there were considerable amounts of fallen leaves in larger pools. In areas such as this we found the majority of shrimp.
Successful breeders have therefore approximated these conditions as far as possible in their breeding tanks.
Responding to demand
When I visited a Taiwanese-Chinese breeding station in China, I gained an insight into its set-up. When interviewing one of Taiwan’s most important breeders I was able to worm out some of his secrets about breeding King Kong, Panda and Red Ruby.
At the station the substrate consisted mostly of fired clay granules without fertiliser, as it does not influence the water. The water itself was very soft, pH slightly acidic to neutral.
That substrate was not directly on the tank bottom, lying instead on an undergravel filter driven by a strong motor-equipped external filter, or in combination with an air-driven sponge filter.
This system was tried and tested in Japan and reduces organic loads to keep the concentration of noxious germs as low as possible.
None of the breeding tanks I saw were overstocked or smaller than 80 l/18 gal, as larger ecosystems are easier to maintain stable.
In the hobby you often see breeding tanks too small with too thin a bottom layer where waste and food rest together and so pose a danger, especially to young shrimplets.
Young shrimp are also quite stationary and move only around a small area, but if there is a high bacterial load or an anaerobic spot exactly in this spot, most young shrimp probably won’t survive.
Well-known breeders who work without undergravel filters vacuum the tank bottom twice a week.
Another important factor for breeding success seems to be a well-aerated tank.
Many shrimp species react badly to a quick rise in temperature — shrimplets first and foremost. Falling temperatures do not seem to be that big a problem, however. Consider this when you net shrimp out to put them into another tank.
It’s also extremely important to adapt them quite slowly to any new water parameters and adding small amounts at long intervals seems to be the secret to success.
For breeding King Kong shrimp and the like, water parameters of 200 microsiemens/cm and a pH of 6.4-6.9 are a must. Temperatures for breeding ought to be 22-24°C/72-75°F, but they can be kept successfully at 17-22°C/63-72°F, similar to temperatures in the habitats.
Nearly all the tanks in the breeding installation were planted very sparingly, mostly with mosses or some Vallisneria. There were smaller pieces of Moor wood with aufwuchs for the shrimp to graze on in all tanks too.
The new colour morphs were kept together with our well-known colour varieties in one tank. The breeder revealed that he does not mate King Kong with King Kong, as this would be the conventional way of doing so, but these high-bred varieties are in a tank where they can mate with Red Bee. Breeders claim that this results in more stable offspring.
I detected a high colour variability among the young in these tanks. Quite a few Panda and King Kong Bees were among the great numbers of shrimplets, although most were still conventional Red Bees with some Red Ruby and a few Blue Bolt or Extreme King Kong Bees.
Pick a colour…
In Taiwan, as well as in other South-East Asian countries, shrimp with a high percentage of black, like Black Diamond or Extreme King Kong, are much sought after.
However, European shrimp lovers seem to prefer animals with white patterns. In Japan, German-bred Black Tiger shrimp are rated far higher than Red Ruby, King Kong, Panda or Blue Bolt.
This article was first published in the December 2009 issue of Practical Fishkeeping. It may not be reproduced without written permission.
Chris Lukhaup introduces the stunning Vampire crab, which is believed to be an undescribed species from the genus Geosesarma.
Quick to seize on unsuspecting live prey, the Vampire crab effortlessly lives up to its name. Chris Lukhaup identifies a twilight terror.
These are omnivorous crabs, but meaty victims make up much of the Vampire’s diet. It eats all kinds of dry food, but also freeze-dried animals as well as earthworms and springtails. From time to time it can also be given live house crickets — and these are ruthlessly hunted down in a flash!
Vampires are crepuscular, feeding at dusk and dawn, and nocturnal, when they also munch on mosses and graze on algae.
It is one of several crabs attracting a lot of interest right now and it is found on an island off the coast of Sulawesi, being shipped regularly to Europe via Jakarta. Until now the species has not been scientifically described and we only have very scant information on its distribution and habitats.
These creatures belong to the genus of Geosesarma. They are fully grown at a body length of 2-3cm/0.8-1.2“ and therefore ideal for smaller aquaterrariums.
Females carry eggs about every six months and, from the eggs, about 50 to 60 young crabs hatch. They should be kept at 22-28°C/72-82°F and amid high humid conditions.
This species has established itself successfully in terrestrial and freshwater habitats and is now totally independent of the sea.
This item was first published in the October 2009 issue of Practical Fishkeeping magazine. It may not be reproduced without written permission.
Limnopilos naiyanetri belongs to the Hymenosomatidae family of false spider crabs and small enough to be called micro crab. Oliver Mengedoht reveals more.
These unusual freshwater crabs lead an exclusively aquatic life and have so far only been discovered in one river in Thailand where they live in water hyacinths. However, in a tank they seem to adapt to other surroundings without difficulty, even prefering to sit on wood than floating plants.
Limnopilos naiyanetri is fully grown when its distinctive, round carapace has reached just 1cm/0.4”. Its basic colour is light grey with patterns on its carapace, claws and legs varying from brownish to light beige.
They also have unusually long legs and can fold them away to appear just half as long.
Legs and claws, called chelipeds, show a strong bristle-like growth and the crab uses these bristles, called setae, to catch food particles and microorganisms drifting by — even including its own pelagic offspring! Consequently, I think that L. naiyanetri are omnivorous if provided with the right range of foods.
At 26-28°C /79-82°F, these crabs seem more active than at lower temperatures, but do not have any problems living within 22-25°C/72-77°F. They are very new to the hobby and have not been kept in captivity for long, but indications are that these animals are very hardy in a aquarium.
Breeding false spider crabs
Limnopilos naiyanetri have relatively large eggs. At the end of gestation females release larvae called zoea, which are believed to develop entirely in freshwater.
Eggs are orange at the start of gestation, then become yellow before finally turning grey. They are about 0.5 to 0.7mm in diameter and are carried under the female’s pleon until the larvae hatch.
Reports suggest that the female occasionally opens its abdominal apron, but sometimes it is completely closed, so the eggs can only be seen through the transparent pleon.
The zoea of L. naiyanetri always move towards light so a permanent source of overtank lighting is essential when breeding to provide the offspring with orientation when swimming around and prevent them from accidentally bumping into the tank’s walls.
Various keepers have failed to raise these crabs beyond the ninth day after the zoea hatched and a conclusive reason has yet to be identified. Many remain determined, however, to discover which parameters will lead to success.
This item was first published in the September 2009 issue of Practical Fishkeeping magazine. It may not be reproduced without written permission.