hermit crabs are good start maybe, I also like emerald crabs, cleaner shrimps and nassirus snails or what ever they are called. the best way to go with a clean up crew is to build them up slowly as the fish increase as they should live off the left over from the fish so if you are only feeding one fish there wont be much for the clean up crew to clean up so maybe start with 3 or 4 hermits and go from there?