Stoplight parrotfish (Sparisoma viride) on a coral reef. The colouration of this fish indicates that it is a supermale. Females and immature males are brown, white and red (see image Z605/1420). The supermale is the dominant male in a given area of the reef, and has his choice of breeding partners. The stoplight parrotfish is a protogynous hermaphrodite: all young fish are female. They change sex as they grow, but only one of the males will develop into a supermale. When the supermale dies another male develops supermale colouration. The stoplight parrotfish inhabits reefs in the tropical western Atlantic, from Florida, USA, to Brazil. It feeds on algae and corals and can reach 64 centimetres in length. Photographed off Bonaire Island in the Netherlands Antilles, in the Caribbean Sea.