Clams are maybe the best kept secret in the hobby. If you can, get your hands on a Tridacnid clam as they are well suited for brilliantly lit tanks. Clams DO NOT need to be fed and will remove nutrients such as ammonium and nitrate ions from the water as a source of food. Clams are very hardy creatures and can with stand extreme changes in water conditions. In 1 year my Tridacnid has almost doubled its size and anchord its self to the bottom of my tank and survived in dismal conditions. Any clam you select will be good. just give them excellent lighting conditions. Happy reefing