Who is eating my fish poop? I have sand substrate in my 90 gallon SA cichlid tank. 2 Black convicts 2 severums 1 jack dempsy 1 fire mouth and 1 earth eater. the possible poop eaters are, 2 rainbow sharks 8 cory cats 3 yoyo loach's or 2 snails. There is never any poop on the ground! Who the hell is eating it? I've had them in the 90 for about 2 weeks, just moved them their from a 55 gallon with gravel.