Limited Resources

Q. I am 14 years old and have been keeping marine aquariums for about eight years. I would like to change an old 20-gallon high tank (24 x 12 x 18 inches) into a mini-reef tank. I know small tanks are difficult to maintain, but I do not have enough money to go for a large system. I already have a minifilter, submersible heater and a venturi protein skimmer suitable for a 75-gallon tank. The hood has only one light.

Everyone says I need at least two lights, but I'm wondering what ballast, end caps and other things are needed. Some people suggest using three or four lights, but how can they fit them over a tank and still open it?

Besides salt and things like that, do I need a substrate? I would like to get about 5 to 10 pounds of large live rock. Would I need actinic lights, and what about filtration? What media goes in the filter — a sponge? How many lights do I need to successfully keep corals?

Can I set this up without spending much more than $75 to $100? What corals should I get? I don't just want mushrooms. Can I keep anemones with them?

A. It is unfortunate, but this is not an inexpensive hobby. What you need to understand is that you have to stay within your resources. Because you have limited funds, you need to be realistic as to what you can do and what you will be able to keep. Many of the gadgets and the equipment we use are built especially for aquariums, and because of low volume sales, prices tend to be higher. However, there are short cuts you can take, such as using equipment from other industries that can make things a little bit cheaper.

For example, your lighting. You will be hard pressed to keep much in the way of corals with only one light. You will need at least two regular output fluorescent tubes, and even these will limit what you can keep to the hardier, less light-hungry species.

Doing things cheaper often means being able to improvise, and sometimes you need to build your own equipment. In your case, you could purchase a simple 2-foot shop light fluorescent fixture for about $25, which you could suspend over your aquarium. Adding some light shades would direct the light downward as opposed to all over the room.

You could also build a simple tank hood out of plywood and place the fixture within this. If you can locate the tank in a place where it will receive a few hours a day of direct sunlight — without overheating the tank — this can add supplemental lighting. As far as tubes to use, I would recommend one daylight fluorescent and one actinic 03, or two full-spectrum tubes, such as the actinic/white from Ultraviolet Resources. A still cheaper option would be to go to a 4-foot fixture instead. This size is the most commonly used in lighting applications in commercial situations, and, as a result, the fixture and tubes tend to be less expensive than 2-foot models.

Many years ago a friend of mine used a 4-foot fixture over a 3-foot tank. He just placed potted plants under the ends of the lights that extended past the sides of the tank!

I would recommend that you use a substrate of fine sand of about 1 or perhaps 2 inches deep. If you use a coarser substrate (1/8 to 1/4 inch) you should make it 3 inches deep. I would use enough live rock to build a pleasing aquascape about three-quarters the height of the tank. I am not sure if 10 pounds will be enough to do this, however, because different types of live rock differ in density quite a bit, and 10 pounds may or may not be enough.

Aquascaping will also prove difficult because your tank is high and narrow, a bad combination for a reef tank. This makes it difficult to place rocks without creating a "brick wall" effect, and provides poor gas exchange. Be sure to leave as much of the substrate bare as possible. You can help achieve this by careful rock placement and by using support structures under the rocks.

As far as filtration goes, I would just use the skimmer you have and get a powerhead for extra water motion in the tank. You can use the minifilter if you like, but you should clean the filter sponge every few days. You can also use it to hold a little carbon.

As for corals, I would recommend button or red button coral (Cynarina lacrymalis), donut coral (Scolymia sp.), hammer coral (Euphyllia ancora), star polyps and mushroom anemones. You will have to experiment with the placement of these corals to find out where they will do best in your tank. I am afraid an anemone would not be a good idea for a tank as small as yours and as poorly lit. Anemones require a great deal of light and can roam around a tank, stinging other inhabitants. The only anemone species that you may be able to keep is Condylactis gigantea from Florida.

And I'm afraid you will be hard pressed to do all of this for under $100, but you will be close. Perhaps you need to do a few more chores around the house!

Fish vs. Corals
Q. I have been into the marine hobby for about two years and have a 240-gallon fish-only tank, a 55-gallon reef and a 30-gallon modified Eng anemone tank. Some interesting developments have come about in the 55-gallon reef system.

I have a very nice octobubble coral that had a button-like coral growing on the lower part of the old skeleton. After a few months it became apparent that the "button" was some type of Fungia species. The thing grew until it reached about 3 inches in diameter. Today I noticed it had detached from its spot and is traveling down toward the tank floor. It left behind a button-size skeleton-like structure. Also, next to that is a small polyp on a stalk. I was wondering if these were offspring, as they had to be underneath the main individual.

In the same general vicinity is a large bubble coral. For the past few months this coral has not expanded fully, but it does not show any signs of disintegration. At times its mouth has been open very wide, so that I can see the structures within. At night it still extends tentacles, but not as fully as before.

My tank parameters are all normal. Nitrates are undetectable (low range test) and phosphates are 0.2 ppm, calcium is at 450 ppm. I have 440 watts of VHO lighting, two 50/50, one full sun and one actinic. I run a protein skimmer on this tank. There is extra circulation from a 403 Fluval (empty) in addition to what is circulated through the trickle filter and sump.

There are two kinds of red macroalgae algae that are flourishing. Green macroalgae is kept from growing by my four dwarf angels and a purple tang. I also have a herd of "reef janitors." What could be a probable cause of the bubble coral's depressed state?

A. The small coral you saw drop off was most likely a Fungia as you suspected. Planulae of Fungia species settle out and develop into a small structure called an anthocauli. The polyp grows in size while attached to the substrate until it reaches a size where it becomes large and heavy enough to break off from the attachment. At this point the coral is now a free-living polyp.

The small stalked polyp you found underneath your Euphyllia is most likely a daughter polyp. You can leave this attached or you can snap it off and reattach it elsewhere in the tank where it can get more light and grow faster. We covered both these types of structures in The Reef Aquarium, Volume One (1994).

As far as your bubble coral (Plerogyra sp.) not opening, there are a few possibilities. First off, your water chemistry sounds fine, so I do not suspect a problem there. Four Centropyge angelfish in a 55-gallon tank, however, are a lot of pygmy angels in a small area! These little "pickers" love to pick at rocks all day searching for food items, such as algae and small crustaceans. I suspect that what is happening to your bubble coral is that the pygmy angels are picking at it. All it takes is a few pecks during the day to keep the coral from expanding fully. The fact that it still expands at night is another clue that it is being harassed during the day.

As to what to do, I am afraid either the offending fish have to go or the coral does. Other possibilities include predatory worms in the rocks, a lack of food or excessive water movement. But I think that if you sat and watched the fish for a few hours, you would see them picking at the coral.