cleaners

Question
Is there a fish that eats the other fish's poo?So cleaning up the tank wont be as hard

Answer
Assuming you have a saltwater tank, there is a wide variety of creatures that will ingest the ditrius created by living organisms. This is comprised of waste, uneaten food and other matter in the system not otherwise digested. One source of keeping a saltwater tank clean is the bacteria living in the system, in filtration devices, live rock, live sand, etc. Another is water changes which will help keep the water at safe levels, still another are the clean up "crew" animals - such as snails, starfish, crabs, sea cucumbers, shrimps and the like. Be careful with sea cucumbers as they can poison a tank if attacked or injured. There are cleaner fish of various types but they usually clean other fish of parasites.