Benthic species feed on sessile invertebrates such as polychaete worms, crustaceans and mollusks. Crustaceans, nematodes, trematodes, and polychaete annelids also serve as parasites. These include crabs, molluscs, sea urchins, starfish and polychaete worms. Here, among algal encrusted rocks live sponges, echinoderms, polychaete worms, sea anemones and other invertebrates. Calcium carbonates constitute the shells of molluscs, brachiopods, and some tube-building polychaete worms. They are planktonic in their juvenile forms, as is typical for polychaete annelids. Naturally "P. monodon" feed on mollusks, crustaceans, and polychaete worms. Those settling on the reef include many other species, particularly crustaceans and polychaete worms. It feeds by diving for insects, polychaete worms, crustaceans, and salamanders. There they feed on algae, barnacles, hydroids and polychaete worms. Analysis of their stomach contents indicates that batfishes feed on fish, crustaceans, and polychaete worms. Juveniles prefer softer-bodied prey such as polychaete worms and sea anemones. They feed on slow-moving invertebrates, such as polychaete worms. Arenicolidae is a family of marine polychaete worms. "Chaetopteridae" larvae are the largest among the polychaete worms.