Micro-Reef Aquarium

Stocking a micro-reef aquarium.

Q. I am in the process of setting up a 10-gallon micro-reef. I have my heart set on keeping a mandarin goby, a cleaner shrimp, a sea horse and a baby chevron tang. I already have an Amiracle skimmer that is rated for up to 60 gallons, and enough live rock to fill a 40-gallon tank. Exactly how much live rock will I need?

I have already seeded the thin layer of substrate I have from an up-and-running tank, and have the skimmer running. How long do I have to wait before I can start adding mushrooms and star polyps to my tank? Also, what smaller supplementary filter should I use in addition to the skimmer, and how often should I change the water?

I am using four standard wattage tubes — two daylight, two blue actinic. Is this enough lighting? I also would appreciate suggestions as to what other corals I could add to my micro-reef.

I am presently adding kalkwasser. Will I need any other supplements?

A. You should use enough live rock to create a structure that extends through a good three-quarters of the tank volume. Now, when I say three-quarters of the volume, I don’t mean a solid mass of rock. The rockwork should be arranged in such a way as to allow maximum water flow and minimum contact with the bottom and with each other. I would avoid using a few large pieces, but instead recommend you use several smaller pieces. This will allow for greater surface area in the system, boosting its filtration capacity and providing more habitat for microfauna.

The mandarinfish you are thinking of keeping will need to graze the majority of its food from the live rock in the system because these fish rarely take prepared foods. I should caution you that a 10-gallon reef system may not, in the long run, provide enough live food for a mandarin. Your lighting and filtration sound fine. However, you will probably need to add a small powerhead for additional water flow within the tank.

You might want to construct some sort of an overflow from which you can pump water to the skimmer. The overflow will remove surface-active compounds more effectively, and allow you to add some filter floss to act as a mechanical filter. This would need to be rinsed every few days. A 10-percent water change once a month should more than suffice for this size system.

In addition to kalkwasser, you may want to consider some of the trace element solutions now available for reef aquariums that contain iodine, strontium and various other trace elements. In the way of test kits you should have pH, calcium, alkalinity and nitrate.

You can start adding the corals you mentioned once you have determined that the pH, calcium and alkalinity are within acceptable ranges. Other organisms you may like to try include zoanthids and juvenile Tridacna clams, such as the aquacultured T. crocea and T. maxima now available. Other corals to consider include small fragments of branching stony corals, such as Acropora and Seriatopora. Just keep in mind that rapidly growing corals such as these will quickly overgrow your tank, and need to be trimmed and pruned on a frequent basis. If fast-growing corals are allowed to become too large they will shade out other species and greatly reduce water movement within the tank.

As already mentioned, the mandarinfish may do well in your system, but you should keep a close eye on it. Check the condition of its abdomen — it should be very round. If you notice that it is becoming sunken in appearance, then it is not getting enough to eat and needs to be moved to another system with abundant live rock. If you want to have the greatest chance for success with this fish I would suggest that you leave small carnivorous fish out of your tank for at least six months. This will allow time for the population of microcrustaceans to increase.

The chevron tang (Ctenochaetus hawaiiensis), while very attractive when small, will grow rapidly. Adults lack the attractive coloration of the juveniles and attain lengths of a foot or more within a year or so. In your small tank it will probably not do this, for a couple of reasons. The small size of the system will reduce its growth rate, and the lack of enough food will also slow its growth. Tangs are constant grazers, and there may not be enough microalgae in your tank to support it. However, they will eat supplemental food.

Sea horses present interesting problems. As you may or may not know, sea horse populations around the world and particularly in Asia (i.e., the Philippines) are under tremendous collection pressure. The main culprit is the traditional Chinese medicinal trade, in which dried sea horses are a valued commodity. The curio trade is another concern, and collection for the aquarium trade is yet another. As a result many populations have become severely depleted.

In aquariums, most sea horses fair poorly due to lack of adequate food. For dwarf sea horses and juveniles of the larger species, newly hatched live baby brine shrimp are the ideal food. Adults of the larger species will feed on live adult brine shrimp, baby guppies or mollies. If you live close to the sea you can also collect grass shrimp or mysid shrimp from inshore algal beds, but this may introduce parasites into the digestive tract of the sea horse. It is possible to wean sea horses from live foods and onto fresh shrimp — thinly sliced or shredded — or onto frozen mysid shrimp. This takes some patience, but once they are taking such foods they will do so with gusto.

Sea horses have a rudimentary stomach and hence cannot store much food. They require frequent feedings to stay in good health. With live food this is not too much of a problem because they can eat when they feel hungry, but once weaned onto prepared foods you need to feed them at least once a day, and preferably twice. In your 10-gallon system they may feed for a short period on microcrustaceans, such as copepods, mysid shrimp (possum shrimp) or gammarid amphipods (side swimmers), but eventually you will have to feed them. If you are prepared to make this commitment, try to get a tank-raised specimen.

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