natural cichlid aquarium

A Natural Cichlid Aquarium

I've been a fan of natural tanks for quite a while. By natural, I mean those that rely primarily on plants and bacteria to break down wastes instead of filtering systems that we humans supply. I've also been a fan of the central American cichlid, Thorichthys meeki, the Firemouth. So, it seemed a reasonable step for me to meld the two, and this is my first attempt to do so.

The tank was first set up in November of 2004, but quickly torn down after a slow leak was discovered (by "discovered" I mean the water had leaked into the adjoining office and was pouring down the steps to the basement, much to the dismay of the secretaries). I resealed it successfully and cycled the tank in February of 2005. The tank is a 45-gallon located in my office at the Mosquito Research Unit of the Department of Entomology, Cook College, Rutgers University. So, my water supply comes from the taps of New Brunswick, NJ. I've treated about half the water that goes in to replenish what has evaporated. I have yet to do a water replacement. I do test for ammonia, nitrites, nitrates, hardness, and pH. All values have been "normal." The fish and plants also appear to be healthy and growing. So far, so good.

The tank is fitted with an airstone, an occasional heater for when it gets really cold (the tank is sits near a window), and four lights. Major lighting comes in from the window, but three fluorescent lights and one incandescent light provide the rest. The plants include primarily Hornwort Ceratophylum. A few sprigs of Elodea and some type of broadleaf can also be found. Lemma, or duckweed is abundant and I do duckweed removal about once a week to prevent the light from being blocked out. The plants appear to be doing well. By increasing the lights through the addition of a two-tube fluorescent and a 60-watt incandescent to the typical aquarium lighting that was already in place, and by maintaining vigilance against the light-blocking duckweed, the plants have responded with new green growth. Usually, I keep the lights on 24-hours, but recently, I begun to turn them off at the end of the day.

Current inhabitants: 2 Firemouths (about 2 to 2.5 inches), 10 Pristella Tetras (Pristella riddleyi), one diving beetle, one caddis fly, 4-5 tadpoles, numerous snails. The beetle, trichopteran, and tadpoles come from a mosquito-gathering trip. The fish are fed live, virus-free mosquito larvae raised from colonies here at the Mosquito Research labs. We also collect larvae in the field, and these too, along with other invertebrates, occasionally get tossed in.

This is a pretty crappy shot of one half of the tank - I'll try to put a better shot up later. This shows the portion of the tank that overlaps with the window. The other half looks pretty similar, with bogwood and rock forming a similar tunnel. Outside, there are crabapples planted, and they block a good deal of direct sunlight.

Interestingly, the fish orient themselves toward the sunlight when they swim past the window.

These are my two Firemouths. I purchased them at Absolutely Fish, a terrific store that is definitely worth the drive for me. They were about 1.5 inches and appear to be growing well. Absolutely fish had two tanks with Firemouths, and one of the tanks had only two Firemouths and both seemed to "tolerate" each other. The top fish (I'll call OneFish for simplicity) is the smaller yet more brightly colored of the two. OneFish will flare the gills and occasionally swim around TwoFish, but TwoFish will chase the former around the plants. I haven't seen really nasty aggression, but it would appear that TwoFish may have the upper hand.

I'm really hoping that I have a male (OneFish?) and a female (TwoFish?) but sexing Firemouths seems to be a lesson on random guessing.

This is as sharp of a picture of Pristella or X-Ray Tetras I'm probably going to get. They are twitchy little fish, but they don't seem too bothered by anything that goes on in the tank. They seem to be a good choice as dither fish for the cichlids. There is no way they are going to be caught as they are rockets compared to the Firemouths more laconic speed. The Gang of 10 includes one truly twitchy individual, one who appears to have a chronic case of the hiccups. They are mad for mosquito larvae and go into a frenzy when fed live food. Their color is wonderful: bright white, black and yellow with a silver and translucent body.

I don't know if they are laying any eggs. If they are, I'm sure the Firemouths are finding them before long.

This too-dark picture shows the caddisfly I picked up on one of the mosquito trips. The case is quite large - much larger than what I'm used to seeing in Idaho. It was in one spot the first day I put it there, but the second day, it disappeared. I don't know if the Firemouths tore it apart.

The diving beetle is still there. I think this is one of the non-predacious diving beetles (Water Scavenger, maybe?) as the legs don't appear to work in unison, but I'm not sure. Hey, I'm an ornithologist (despite working in an entomology department).

Update on the diving beetle: He seemed to survive well, tooling around the tank near the surface, and then zooming around the sides. But he was really difficult to find, and I think he may have gone with the overgrown plants that I discarded about three weeks later.

I occasionally see a water mite or two (very tiny, red, tick-like acarids) that came in with the mosquitoes. The firemouths picked them up, but spit them right out.

So, that's my tank.

Well, I went away for about a week, and the tank got terribly overgrown, with much of the lower parts of the plants dying. I replaced them with more hornwort, elodea, mryiophyllum and two swordplants. I also added a divider because after the replanting, there was far less cover than before, and OneFish was getting the poop kicked out of him even more. The divider is actually equipment from a grad student's mosquito experiment (how big of a screen will they fly through?). The Pristellas swim through easily, but tend to stay on the side with TwoFish. OneFish immediately perked up and wounded fins healed.

I also added some aquatic sand for the firemouths to sift through. They bulldozed around, spraying sand through their gills, and spreading around the wealth. It also gave me a place to drop cichlid pellets without them getting too deep in the substrate.

I'm not as thrilled with this setup as with the loose, haphazard array of before. It looks too artificial, without the rough chaos of nature. But if the fish are happy, I can live with it.