Its diet primarily consists of algae, seagrasses, cnidarians, sea cucumbers, gastropods, polychaetes, shrimp, and crabs. It feeds on amphipods, polychaetes, and mollusks. "M. canis" feeds mostly on crustaceans, polychaetes, and mollusks. Olive flounder typically eat fish spawn, crustaceans, polychaetes, and small fish. Many samples were collected, for example, bivalves, polychaetes, large crabs and Riftia pachyptila. Their diet consists mainly of fish spawn, crustaceans, polychaetes and small fish. It is active at night and feeds on polychaetes, crustaceans and bivalves. They have also been shown to exclude or inhibit polychaetes, cumaceans, and amphipods. A flounder's diet consists mainly of fish spawn, crustaceans, polychaetes and small fish. Traditionally the annelids have been divided into two major groups, the polychaetes and clitellates. It may also include crustaceans and polychaetes. The blood of most annelid worms and some marine polychaetes use chlorocruorin to transport oxygen. It is mostly a night hunter, feeding on small fish, polychaetes, cephalopods, and crustaceans. Meiofaunal composition at the Marina Beach chiefly includes turbellarians, nematodes, polychaetes, oligochaetes, and harpacticoids. Underwater polychaetes have eversible mouthparts used to capture prey.