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
Crown-of-thorns starfish of a proportion of individuals with regenerating arms. A variety of about 11 species have been reported to prey occasionally on uninjured and healthy adults of "A. planci". All of these are generalist feeders and none of these, however, seems to specifically prefer the starfish as a food source. This number, however, is probably lower, as some of these presumed predators have not been witnessed reliably in the field. Some of those witnessed are: Gonads increase in size as the animals become sexually mature and at maturity fill the arms and extend into the disk region. The ripe ovaries and