Shortfin lionfish (Dendrochirus brachypterus) resting on a sponge. This fish inhabits coral reefs in the tropical Indo-Pacific region, from the Red Sea to the Pacific islands. It feeds mainly on small crustaceans, which it sucks into its mouth with a huge gulp. The long spines in its fins contain a powerful toxin that deters predators and can deliver a very painful sting. It can reach a length of around 17 centimetres. Photographed off Sulawesi, Indonesia.