Scallops are non-photosynthetic filter feeders that are generally found on rock reefs and coral reefs.  They usually have brightly colored tissue and an oblong hinged shell.  If Scallops are well fed and unbothered, they will remain in the same spot, however, if they are under attack, they will use their shells and clap themselves out of harms way.  Scallops are peaceful and do well in very clean waters, but require plankton type foods to stay healthy.