Great fish, won't do a thing for your sandbed. A fighting conch, some cerith and nassarius snails, and an atlantic cucumber are good options for the sand. Sandsifting fish do more damage than good to a sandbed by eating the needed infauna from the sand. Lawnmower blennies will rasp algae from the rocks and glass.What size is your tank? How long has it been set up? And what is it you are trying to remove?