Stonefish (Synanceia verrucosa) camouflaged among coral. Its curved mouth is seen at lower centre. This solitary fish inhabits reefs of the Indo- Pacific region, indistinguishable from the rocks amongst which it hides. The stonefish feeds on smaller fish and crustaceans, and grows up to 40 centimetres in length. The fins along its back (not seen) contain poisonous spines, used in defence. It is the world's most poisonous fish and can be fatal to humans unless a serum is applied immediately. Photographed in the Red Sea.