Crown-of-Thorns Starfish

ID points

• A dozen to twenty arms, covered all over with long venomous spines
• Everts its stomach straight onto the coral and digests it there
• In outbreaks it can strip a whole reef down to white skeleton

Basics

Family

Acanthasteridae

Length

25–45 cm

Depth

1-30 m

Regions

Indo-Pacific reefs

Distribution

Tropical coral reefs of the Indo-Pacific

Diet

Live coral polyps

Easily confused with

Cushion StarArms completely reduced, the whole animal like a five-cornered bunBarrel SpongeA huge barrel-shaped body with a deep central openingBlue StarfishEntirely saturated cobalt blue, with no other markings

Fun fact

The Crown-of-Thorns Starfish is armoured all over in venomous spines and feeds on coral polyps. During a population outbreak a single individual can destroy around 6 square metres of coral in one year, making it one of the gravest threats a coral reef faces.