Where do Crown of Thorns live?
Crown-of-thorns starfish
The adult crown-of-thorns is a corallivorous predator that usually preys on reef coral polyps.[18]  It climbs onto a section of living coral colony using the large number of tube feet on its oral surface and flexible body. It fits closely to the surface of the coral, even the complex surfaces of branching corals. It then extrudes its stomach out through its mouth over the surface to virtually its own diameter. The stomach surface secretes digestive enzymes that allow the starfish to absorb nutrients from the liquefied coral tissue. This leaves a white scar of coral skeleton which is rapidly infested with filamentous algae.[19] An individual starfish can consume up to 6 square metres (65sqft) of living coral reef per year.[20] In a study of feeding rates on two coral reefs in the central Great Barrier Reef region, large starfish (40cm and greater diameter) killed about 61cm²/day in winter and 357–478cm²/day in summer. Smaller starfish, 20–39cm, killed 155 and 234cm²/day in the equivalent seasons. The area killed by the large starfish is equivalent to about 10m2 (110sqft) from these observations.[21] Differences in feeding and locomotion rates between summer and winter reflect the fact that the crown-of-thorns, like all marine invertebrates, is a poikilotherm whose body temperature and metabolic rate are directly affected by the temperature of the surrounding water. In tropical coral reefs, crown-of-thorns specimens reach mean locomotion rates of 35cm/min,[22] which explains how outbreaks can damage large reef areas in relatively short periods.