My cichlids did this too, but I put them in with my 50+ guppy fry in a 10 gallon tank. Your tank size should be good, but just make it a bare bottom tank. Much easier to work with. my fiancee and I have a filter running at all times, but we still clean the bottom of the tank every day. Also, try going to you LFS
and find a food called "First Bites". I use this on all of my fry and they all are healthy and any that have grown to adult size are healthy and breeding. Hope this helps.