Distinctive Characters: Dorsal fin with 7 spines and 13-14 rays. Anal fin with 2 spines and 9-10 rays. Pectoral fin with 16-18 rays. Body depth 2.3-2.8 in standard length. Body oblong. A small fleshy flap on tip of chin. The spinous portion of dorsal fin separated from the soft portion by a deep notch. Margins of subopercle and inter-opercle smooth. Caudal fin rounded.
Colour: Body dark brown or black with thin, pale stripes. The number of stripes tends to increase with age, and they also tend to break up into a series of dashes.
Habitat and Biology: Inhabits coral reefs and rocky bottoms where there is good shelter, often in surprisingly shallow water. Feeds mainly on fishes.
Distribution: Indo-West Pacific.
Remarks: Grammistes sexlineatus, like other soapfishes secretes copious quantities of mucus (grammistin), particularly when disturbed. Previously recorded under the family Grammistidae.