u need some small hermits to help clean up in your tank
please give some more specifics of your tank...
size, amount of rock, time its been up, filtration, etc that way we can help and point u in the right direction
one fish would only need to be feed depending on the fish once every 2 days a half a cube of frozen food or switch with different kinds for better health and colortatin
what do u feed your fish and what kind of fish