The slender grouper is a medium-sized fish growing to a length of about 65 centimetres (26 in). The head occupies 40% of the total length and the mouth is large, with the lower jaw longer than the upper jaw. There are no palatine teeth, a fact which distinguishes this species from other groupers. The basic colour is pale reddish-brown liberally dotted with orange spots which are closer together on the head. There are five pale silvery blue longitudinal lines running down either side, the lower 3 reaching the tail but the upper two breaking into irregular streaks. The dorsal fin has 11 spines and 14 to 16 soft rays. The anal fin has 3 spines and 8 to 9 soft rays. Juvenile fish have vivid blue and red longitudinal stripes. The slender grouper has a wide distribution in the tropical Indian and Pacific Oceans. The range extends from the east coast of Africa and the Red Sea at 32°E to southern Japan and Australia at 171°W. It is found on coral reefs and seaward reef slopes and in lagoons at depths down to 50 metres (160 ft) or occasionally 80 metres (260 ft).
