The Ring Tail Cardinalfish (Apogon aureus) belongs to the ‘Cardinalfishes’ family Apogonidae and is a tropical species that is widespread throughout the warm waters of the Indo-Pacific region and is common in the reefs of South-east Asia. Cardinalfishes are unique in that males carry the fertilised eggs in their mouth and then care for the young when they hatch. Adults can be readily identified by the black band around the caudal peduncle (base of tailfin) whilst in juveniles it is a large black spot. It can be found living on coral reefs from depths of 1 to 50 metres and adults often pair up in amongst aggregations. It is generally found under overhangs, on shipwrecks or in amongst branching corals. The Ring Tail Cardinalfish (Apogon aureus) grows to a maximum length of approximately 14cm.