Can sand fleas get in oyster shells?

Sand fleas, which are actually crustaceans known as amphipods, typically inhabit sandy or muddy coastal environments and do not usually enter oyster shells. Oysters themselves have a hard, closed shell that provides protection against predators and parasites. While some small organisms may find their way into oyster beds, sand fleas are not known to be among them, as they prefer to live on the surface of the substrate rather than inside shells.