Crown-of-thorns starfish substrates with their arms and, when offered a choice of substrates, tend to settle on coralline algae, which they will subsequently feed on. In the classic pattern for echinoderms, the bilaterally symmetrical larva is replaced by a pentamerously symmetrical stage at metamorphosis, with the latter's body axis bearing no relationship to that of the larva. Thus the newly metamorphosed starfish are five-armed and are 0.4–1 mm diameter. (Note the size of the tube feet relative to the size of the animal.) They feed on the thin coating layers of hard encrusting algae (coralline algae) on the undersides of dead coral
Reef starfish Reef starfish Reef starfish (Stichaster australis) is a species of starfish found in the South Pacific Ocean around New Zealand. A keystone species, the carnivorous starfish plays an important part in reducing the expansion of mussels. "S. australis" is pink or purple in color, with 11 arms. Found throughout New Zealand, "S. australis" is a keystone species in both the North and South Islands, playing an important role in mussel predation. In one study on the west coast of the South Island conducted in the 1970s, "S. australis" was found to have removed a majority of transplanted mussels within two