Sea Stars, like all echinoderms, have a five-part body plan with a central disk and 5 to 50 radiating arms or rays. The surface is knobby, spiny, smooth or bristly due to its skeleton of calcium carbonate ossicles (rods, crosses or plates) buried within the skin. The mouth is found on the underside and the anus is found on the upper. These animals have 2 or 4 rows of tube feet on their ventral side tipped with suckers that allow them to feed or move across the substrate.

Crown-of-thorns Star
(Acanthaster planci)

The Crown-of-thorns Star feeds on living coral polyps, usually Pocillopora meandrina, and leaves white patches of dead coral in its wake. It is about 18" with 12-19 arms covered with stout, sharp and venomous spines. Punctures in humans usually produce pain, swelling and numbness that will disappear in about 48 hours. Triton's Trumpet snails prey on Crown-of-thorns, as does the tiny Harlequin Shrimp.