all their fins have rotted away but there are no physical signs of distress or white fuzzy pimply spots either. 2 out of 3 cats have no top or side fins, the tail is fine & they are good eaters so are very fat cats. the 3rd cat has most his finnage but don't know why he is doing better than his bigger friends. my other fish have no signs of tail rot - 4 silver dollars, a medium & a baby tri-color bala sharks, 2 fat blood fins, 1 beta & 1 pleco. anyone know why & also give me advice on how to cure them? thx all.