GEORGETTE DOUWMA / SCIENCE PHOTO LIBRARY GEORGETTE DOUWMA / SCIENCE PHOTO LIBRARY
Male sergeant major (Abudefduf saxatilis) guarding his egg patch (red). This fish is usually silver with black bars, but the colour of the male changes to this blue when it is guarding the eggs. This fish inhabits shallow waters in the tropical and subtropical Atlantic Ocean, from the northern USA to Uruguay in the west, and from Morocco to Angola in the east. It feeds on zooplankton, small fish and crustaceans and algae, and can reach a length of around 23 centimetres. Photographed off Bonaire Island in the Netherlands Antilles, in the Caribbean Sea.
Model release not required. Property release not required.