i would say not to get a clam of any sorts unless you are going with MH lighting....a lot of times cleaner clams and such will just buy themselves, you'll never see them and they will die and pollute your tank...i have a 30g tank...i have a full blown reef though....i run no skimmer hang on only....its been set up for about a year...i have about ten hermits, four emerald crabs,six snails a mixture of a bunch, a cleaner shrimp,and a lawnmower blenny....that is my clean up crew....then i also have a few fish....very over stocked but they are all happy and have been prospering for a year....also all my levels are perfect....