The plain maskray generally hunt at the surface of the bottom substrate , rather than digging for prey . Its diet consist predominantly of caridean shrimp and polychaete worms . Small bony fishes are also eaten , along with the occasional penaeid prawn or amphipod . Larger rays consume a greater variety of prey and relatively more polychaete worms when compared to smaller rays . This species is parasitized by the tapeworm Acanthobothrium jonesi .