Ring-tailed cardinalfish, Apogon aureus. Red Sea and East Africa to Papua New Guinea, north to Japan, south to Australia. A coppery-coloured fish with a broad blackish bar at the base of the tail up to 14.5cm in length. The upper jaw has a narrow blue streak, and a broad blackish stripe extends from the front of the snout to the eye. Easily confused with Apogon fleurieu, where the black tail bar does not narrow in the centre, but unlike this species the stripe is also present in juveniles.
Inhabits holes in rocks or under ledges in shallow waters. Known to occur in mixed aggregates with Apogon apogonoides during summer and autumn, but form separate aggregates in winter and spring.(text source: Wikipedia)