Nearly two years ago, I brought one of those tiny 1-gallon desktop fish tanks, and four gold and silver danios to go in it. One was an early victim of cat-fishing, but the other three have made it to this day. Encouraged by this success in the previously unproductive field of fishkeeping, I had been thinking for a while of buying a slightly larger tank, and last paycheck's treat to myself was purchasing a 6-gallon one. Still small, of course, but I have a very tiny apartment.
Last weekend I set the new tank up, with some plants and a bit of driftwood, and after letting it run for a couple of days, I mounted the scratch danios... er, a couple of additions to my danio school. Fish sites inform me that danios require at least 5 to starting shoaling, and I figured that if the log had brought some hideous poison or the plants turned out to be Danio Death, that I'd rather the new ones croak than the ones I was attached to.
They failed to turn belly up, so tonight was Operation: Fish Transfer. I managed to wangle all three into separate plastic bags -- trickier then it sounds, since the desktop aquarium is a triangle about six inches on a side with a tube in the middle. Then they were all popped into the aquarium to equilibriate while I cleaned the tank.
This is where my clever plan went wrong. One of the danios in the little tank had had a bit of white fluff on its mouth for a couple of weeks. In case this was cotton-mouth, I had been dosing the tank with Melafix. I had intended to transfer the two healthy fish, do a water change on the little tank, and then use it as a hospital tank to treat the white-mouthed one. Except that the process of catching the fish, vacuuming the gravel for the first time, and then pouring in the new water had kicked up so much crap that it was clearly going to take a day to settle, and the process of chasing them down had been so stressful for the fish that I couldn't see doing it again.
So I finally ended up releasing it as well, and now the five are swimming around the tank. The three transfers are clearly a little stressed, but I'm hoping not enough to kill them.
The amusing thing to watch, though, is the way the groups interact. The new danios came from a big tankful and are used to schooling, while my three have been hanging out as a trio for years, and in a tank too small to do much serious swimming. So one of the little golds has glommed onto the big danio that was the tank boss, and is trying to school with it. And the big gold is very nonplussed as to why there is a tiny fish glued to its side. I can practically hear the little gold going 'no! no! you shoal like THIS! stop turning the other way! no darting!'