Crown-of-thorns starfish occurs where coral reefs or hard coral communities occur in this region. The body form of the crown-of-thorns starfish is fundamentally the same as that of a typical starfish, with a central disk and radiating arms. Its special traits, however, include being disc-shaped, multiple-armed, flexible, prehensile, and heavily spined, and having a large ratio of stomach surface to body mass. Its prehensile ability arises from the two rows of numerous tube feet that extend to the tip of each arm. In being multiple-armed, it has lost the five-fold symmetry (pentamerism) typical of starfish, although it begins its life cycle with
Stichaster striatus these were sessile organisms. It was not found to engage in cannibalism of its own species or to feed on other species of starfish. Many individuals were found to have missing or regenerating arms. This is likely the result of attacks by the dominant predatory starfish in the region "Meyenaster gelatinosus" and "Luidia magellanica". Starfish with missing arms are likely to have a certain minimum size; this is because, if they are too small, they are entirely devoured by the predator which attacked them. Juvenile "S. striatus" are found among the holdfasts of the kelp "Lessonia nigrescens" or hiding in