Well, flame scallops are supposed to be almost impossible to keep. Some reasons why:
1: They don't get enough to eat (the scallops cannot recognize bottled phytoplankton- those are simply too large) basically they eat things similar to carnation corals. IF you can provide appropriate foods (need a very large established tanks), then provide a constant source of food via drip system.
2: They often are moved by aquarists too often to a more "visible location". The scallops are very reclusive.
3: Harassment by fishes/invertebrates.