I had heard this about fish, but my ghost shrimp seem to get excited when my fish poop. They run out of their hiding places before the "load" hits the ground and pick at it together.There is nothing that will eat animal waste, but there are things that will scavenge leftover food, plant debris, and algae, such as; shrimp, plecos, cory cats, snails, and other sucker mouth species like whiptail cats and oto's will eat algae/bio film but not leftover food and plant debris.