Quick guide to modern marines


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Marine keeping has changed rapidly in just a handful of years — and very much for the better. We look at the latest trends and tastes.

So perhaps it's a good time to reflect on just how far this hobby has progressed — and none more so than with marines. The best part of this progress, however, is that our livestock is all the better for it.

So what makes a successful modern reef:

Tank shape
The ‘make it as tall as you can’  tank has largely gone out of the window in favour of greater width, front to back, over height. Tanks 60cm/24” plus look great but present problems. Not many reefkeepers can actually touch the bottom of tall tanks, making aquascaping, coral placement and maintenance difficult.

The new marine tank will be wider than taller for greater surface area for gaseous exchange, larger territories for fish, more space for aquascaping — and greater width creates a more realistic vista.

A wide, shallow tank doesn’t need such thick glass, making it cheaper, or as powerful lights, because they don’t need to penetrate great depths.

You also get to view from above, which, when you have a colourful mixture of coral reef fish, looks very nice.

Open topped, rimless, braceless tanks made from low-iron OptiWhite glass are the new cool.  

Every mouth needs food!

Feeding means catering for corals as well as fish and this aspect of the hobby has also progressed for the better.

Dry foods for fish have come on apace. Increased nutritional values and visual appeal mean that marines may be better off with dry foods as a staple and frozen foods as treats. If they won’t take dry, frozen foods can be enriched by soaking or spraying.

Coral feeding is essential in a modern reef aquarium. The owner will have several coral foods of varying sizes, from green phytoplankton to zooplankton, which itself can vary from invertebrate eggs and rotifers through to Mysis and krill. Feed your fish and corals and the circle of success with marines is complete.

LED lighting

Metal halide is making way for multiple, linear T5 fluorescent tubes and LED and LED lighting is viable for growing corals — even on its own. You just need enough of it to make up the equivalent PAR values of lighting being replaced. Take the LED route for shimmer and lowering your carbon footprint. Take the T5 route for colour.

Or how about the best of worlds by combining LED and T5? It’s all possible and available, and pushing the hobby forward. We’ve seen the 100w household electric light bulb banished for lack of green credentials. Will metal halide go the same way?

As well as the way we view our fish and deliver our light, the way we control that light is also changing. LED is super versatile when it comes to control. Dim down, dim up, colour changes, cloud cover; you name it!
However, if you keep very bright light-demanding corals you will still need more than the normal recommended amounts, regardless of type and format.

Today’s filters
If using an external filter with biological media, as per a freshwater set-up, you will have problems with nitrates.

A modern marine keeper will have to totally re-learn marine filtration principles.

Natural nitrification from live rock is still key in 99% of set-ups and the Berlin method of live rock and a big protein skimmer is still the most successful marine method. Only now some people are using a twist…

Bolt-on nitrification and denitrification methods have gone, including plenums, deep sand beds, mud systems — all with or without algae refugiums. Of those, deep sand beds and mud systems remain popular, with or without algae refugiums, and many will be used along with the Berlin method for greater denitrification – meaning a reduction in nitrates.

A sand or mud bed in a sump away from the fish also adds to invertebrate diversity.

Coming back to the twist, however. We have recently seen the birth and acceptance of ULNS: the Ultra Low Nutrient System. This is designed to be run alongside live rock and large skimmers and aimed at lowering nutrients with the combination of zeolites — a chemical media usually only used in freshwater systems, and bacterial strains that will tightly cycle what’s left of the nutrients, making them unavailable to algae.

The Ultra part of ULNS though means that this bacteria dosing and zeolite cleansing brings levels of nitrates and phosphates to virtually undetectable levels, starving nuisance algae and making it unavailable, even for use by photosynthetic, symbiotic algae inside coral tissues.

The result is no more brown SPS corals, but stunning pastels like pink, violet, and yellow. This is expensive but so modern.

Increasing flow
The more we find out about water flow on coral reefs, the more we increase it in our aquariums. Say goodbye to ten and even 20 times volume turnover, and hello to 50 times or greater. With water flow it is all about how you deliver it.

If we still used conventional powerheads at similar outputs they would tear corals from their rocks, and no fish could swim against them. Yet deliver 10,000 lph through a 5cm/2” outlet and a broad flow is created, powerful enough to lift detritus and deter slime algae, but gentle enough to bring food to corals and wash away waste.

The flow in marine tanks should also be variable, alternating, or even random. Fish and corals can daily get by with the same old flow, but you won’t be imitating a reef and it won’t be what your fish or corals have been adapted to.

Plug-in wavemakers are widely available and inexpensive. Buy an electronically-controllable pump and controller and you can set wave patterns, fade in and out, and even create calm water at night with a photocell. Some are even PC compatible.

Minerals on demand
Take a look at the marine dry goods section of an aquatic store and these days you will see bottle after bottle of supplements. Are there more than there used to be — and do we need them? The answer to both questions is yes.

Getting the flow, nutrient levels and lighting right means that our corals should now be spending more time  growing and less time struggling, and this means they need ample minerals in the water to extract and build their skeletons.

The more growing corals you have, the more these mineral demands will be.

A good salt will be perfectly balanced, if mixed correctly, which is a good start, but if you don’t replenish the minerals with water changes and new salt the mineral values will become depleted.

Enter the supplements! Modern reefkeepers will be aware of not just the necessary pH for coral growth (8-8.6), they will also be testing for alkalinity, measured in dKH, calcium and magnesium, measured in parts per million. Keep the desired levels like that of natural sea water and your corals will grow.

Supplements in liquid or powder form are the order the day, but you must test to know how much to put in. Overdosing can be just as bad as not dosing at all.

The modern doser will calculate the requirements of the system by regularly testing and determining how much of each mineral is being used up between tests.

Automatic dosing is now quite common in the hobby and will become more so as more people adopt stony coral culture, which are the most demanding of minerals.

Mentioned more and more in marine fishkeeping circles, the Balling method is one of the ways that essential minerals can be delivered to aquariums that have a high mineral demand.

Combined usually with an automatic dosing pump, KH, calcium and magnesium can be topped up automatically throughout the day and in very small, accurate doses.  Adjust them to your coral’s demands.

Replicating nature
This is one of the largest visible changes. For too long we have placed corals on rock piles like fruit on a market stall. You know the format: a rock pile stacked the length of the tank, uniformly sloping front to back, bottom to top. Light demanding corals were placed at the top, undemanding corals at the bottom and overall, it worked. Not really representative of a reef though…

A natural reef is far more open and intricate, and structures aren’t made up of dense piles of similarly sized rocks. Instead they comprise generations of coral skeletons that have lived and died, each time growing on top of the old one. The aquascape defies gravity with caves, overhangs, peaks and gullies. The hard corals actually make the aquascape, not the base rock.

Modern reefkeepers and aquascapers are getter better at replicating nature. Rocks are being chosen for looks as well as biological filtering capacities. If owning a sump you can always put your most porous Fiji rock in it for filtering and have the less porous, more decorative branching rock in the main tank for reef building.

You can even use dead live rock, (reef bones) and aquascape the main tank dry, taking time to get the aquascape right before filling. Seed with some mature live rock and bacterial formulations and it will be live again in a few weeks.

So how do you create a gravity-defying aquascape? Use aquarium silicone, aquarium grade aquascaping putty or, for overhangs and bridges, tie rocks together with plastic cable ties, plastic nuts and bolts or drill holes in them and thread them onto plastic rods.

When experimenting with these techniques your reef aquascape can move up to a whole new notch. And what’s better about a more open aquascape? Better water flow with fewer dead spots.

Choosing your livestock

Is it possible to select modern-looking livestock? Surely they look like they always did? Well they do, but it is the species you choose and numbers you keep them in that will create the modern look.

Convention dictates keeping one of everything; one tang, one dwarf angel, one damsel because it killed its tank mates, one firefish, one goby and one wrasse. Yet many of these fish don’t live solitary lives in the wild and will lack environmental enrichment if they cannot interact with members of their own species.

The modern reef is all about being more natural, so shoals, or pairs of fish are the order of the day. Add a shoal of cardinalfishes and, if you are a good reefkeeper, a shoal of Anthias. In really big tanks add a shoal of Yellow tangs and a really big shoal of Green chromis. Wrasse pair up surprisingly easily — and how about a stunning pair of Leopard wrasse?

Clownfish are an interesting proposition because they are always kept in pairs, yet they don’t naturally inhabit the high light, high flow, high energy reef crest SPS coral environment we are replicating. Be brave and leave them out.

Mobile inverts can be clichéd as well. Instead of keeping one cleaner shrimp, one Blood shrimp and one Boxing shrimp, only add mobile inverts that make a difference, like Peppermint shrimp for Aiptasia, Emerald crabs for bubble algae and Sand sifting starfish to keep the substrate turned over.

Coral choice used to be governed by what we could keep alive. Soft corals were the survivors so we kept them, yet imagine a wild coral reef. All those interesting shapes and colours are mainly made up of hard corals!

Choose colourful corals that occupy the same niches in nature. SPS with SPS, and LPS with LPS. An actual biotope may contain lots of corals from only a few species. This can be done easily by fragging and will look much more realistic. Create a biotope by researching which fish and corals come from and where. It’s no different to what freshwater specialist fish keepers do.

Depending on lighting and livestock preference you could create a deepwater reef, with blue lighting and non-photosynthetic corals. You’ll be amazed to discover just how many of ‘our’ reef fish naturally live below 40m/130’. Beyond that point the only light penetrating is blue and red coloured animals become camouflaged.

It’s when we keep our livestock as they would live in the wild that we will get more success in breeding too.

This item was first published in the December 2009 issue of Practical Fishkeeping. It may not be reproduced without written permission.