Killifish in a Community Tank
by Jim Warner
While most of my killies are in breeding sep-ups in the fishroom, occasional impulse buys and home bred juveniles end up in one of my four community tanks which are roughly divided into fish of the same size.
I have found that Aphyosemion australe, & Chromaphyosemions are the most well behaved with small fish (e.g. Cardinal Tetras, Cherry Barbs, Bumblebee Gobies, etc.) Although the australes did take exception to the Poppendata furculata, which I put down to the wagging tail of this fish while holding station in flowing water.
Aphyosemions gabunense and striatum are less well behaved, nipping any fins which come within reach, and, in the case of gabunense, pursuing the unfortunate victim for some distance. Since A. striatum tend toward the upper reaches of the tank, most of the other fishes were spared the continued harassment, but I found that the marble hatchetfish didnt have much of a tail left after a week or so in their company. Surprisingly, Fp. spoorenbergi and Panchy. playfairii juveniles did not cause too much trouble in this tank. One of my bigger mistakes was introducing Ep. zimiensis. I added two pair and all seemed fine for a couple of weeks...and then the bodies started to appear. I didnt catch on until one evening I noticed three Ep. zimiensis lurking with intent at the bottom of the tank...an odd place to see Epys. I saw a flurry of activity under a piece of driftwood and upon investigation found the other Ep. zimiensis shaking a male guppy vigorously by the tail! Needless to say, the culprits were moved on to play with the big boys after that.
In a two foot tank for very small species (e.g. Spotted Rasboras, Gelius Barbs, Sparkling Gouramis, etc.) I have kept the following species (at various times) without aggression: A. Dargei, juvenile A. calliurum, macrophthalmus and Ep. annulatus. In another tank I am currently keeping Pachy. playfairi males, A. marmoratum males and A. Striatum females in apparent harmony.
My biggest embarrassment was putting a male betta in a tank which already contained a pair of Fp. gardneri Biassa. It took seconds for them to notice the newcomer with the long tail and chase it relentlessly around the tank (in spite of being half its size) until I could rescue it! The image of a tattered, shell-shocked betta being lifted to safety in a net with a male Fp. gardneri hanging onto its tail like a dog with a bit of rope will serve as a constant reminder that one must carefully consider community tank mates.