fry swimming funny (what's going on?)

[Madkour]

i have about 60 or so cacatuoides fry in a 10 gal with two sponge filters, java moss and a heater. i've been feeding them frozen bbs 2-3 times a day by shaving a tiny piece from one of the cubes and distributing it around the tank with a syringe. i often see them eating (though they do a lot of spitting the food out). some have grown quite a bit, and during the first week i didn't loose any. now a bunch are just lying around the bottom, others are swimming vertically and i've lost three with about five more looking ready to go. the ones that are healthy are obviously longer and fatter. am i feeding too much, too little, or could it be a disease? is it just a fact that one will lose a bunch of fry? could they be deformed? ammonia and nitrite are both 0 and i do 25% water changes every day to every other day.

 

[Allivymar]

I don't know much about Apistos, but I do know Angelfish and other cichlid fry have similar probs. The ones that sit on the bottom are usually called "belly sliders" and it seems to be a prob with the swim bladder. Unfortunately it isn't curable if thats the prob and the fish are culled. It seems to be related to water quality and bacteria. Frequent vacuuming of the BBS right after they fry are done eating seems to help avoid belly sliders. This is assuming, of course, that my guess is a correct one.