The Crown-of-thorns Starfish (Acanthaster planci) is a type of sea star. Usually, they have orange-red to purplish skin, with yellow or pink spikes on their skin. These bright colors are to warn animals that may want to eat it that it is venomous. The Crown-of-thorns is also the second largest sea star in the world, as it has a diameter of up to 3 feet.Only the Giant Sunstar is bigger.
It only feeds on coral polyps, and usually at night. The Crown-of-thorns climbs over its prey, releases digestive enzymes to break down its food, and then absorbs the coral polyp, which has now turned into a liquid. What's left behind by the sea star is the leftover coral skeleton.
Effect on Coral Reefs[change]
The Crown-of-thorns is well known for its destructive habits of eating coral, which may lead to the destruction of coral reefs, such as the Great Barrier Reef. Usually, when there are not too many of them, these sea stars help maintain the coral reef by preventing the faster-growing coral from taking over the coral reef. However, when there are too many Crown-of-thorns, they can devastate a coral reef.