The sooty grunter is a relatively large species of grunter. It is brownish-grey to sooty-black with darker scale margins, although some specimens may show golden blotches on the sides. The juveniles possess dark blotches on the
anal fin and the soft-rayed part of the
dorsal fin. There is a discontinuous lip fold on the ventral side of the lower mandible. As they grow, some individuals develop thick, fleshy lips. They have a moderately deep body which is oblong to oval in shape, laterally compressed, and a dorsal profile which bulges between the nape and the start of the dorsal fin. It has an oblique mouth, with the
maxillary reaching the level of the front edge of the eye in the young, but as the fish grows, the gap between the eye and the maxillary increases. The teeth are conical and a little recurved in shape, and are arranged in bands, with those in the outer rows the largest. There are no teeth on the roof of the mouth. They have a continuous dorsal fin which contains 11-12 spines and 12-14 soft rays; the spiny part is arched with the fifth to seventh spines the longest, and the rays are longer than the spines. The anal fin contains three spines and 8-10 soft rays. The
caudal fin is marginate. They have been recorded to have attained a maximum
fork length of , although they more commonly have a
standard length of around ; the maximum weight of . ==Distribution==