Ribbon Sweetlips

Plectorhinchus polytaenia is a species of grunt native to the Indian Ocean and the western Pacific Ocean, where they can be found on coral reefs at depths from 5 to 40 m (16 to 131 ft). This species can reach 50 cm (20 in) in TL. It is important commercially as a food fish.

Description

Colour: brown to yellowish grey with 5 to 9 fairly narrow grey or white longitudinal stripes outlined with dark brown on body and continuing around snout. Fins are yellow, soft. Dorsal, caudal and pectoral fins are with darker stripes disappearing with age. Eye and lips are yellowish. Mouth, tongue, and gill rakers are scarlet. Chin is white. Juveniles have fins striped and fewer stripes on body. Juveniles have black stripes and live alone on rubble slopes in deep water. As they age, the black is reduced to an outline, and the stripes become more yellow; increasing stripes develop with age. Their bright colors help them blend into the coral in which they live. Dorsal spines (total): 12 - 13; Dorsal soft rays (total): 19-22; Anal spines: 3; Anal soft rays: 7 - 8. This species is distinguished by the following characters: chin with 6 pores, no median pit; gill rakers on first gill arch 7-9 + 1 + 17-20 = 26-29; Dorsal XII (rarely XIII), 19-22, 3rd-5th spines longest; lips fleshy, moderately swollen with age; scales ctenoid (rough to touch); lateral line tubed scales about 54-60; body depth 2.6-2.9 in SL; caudal fin rounded to slightly emarginate.

Distribution

Indo-West Pacific: west coast of India; Philippines and Indonesia to Papua New Guinea, south to northern Australia.

Habitat

It occurs on coastal and seaward reefs. Adults are on deep, current-prone slopes with rich invertebrate growth. Juveniles are on sheltered reefs nearby. It is found singly, in small groups under ledges or large resting aggregations by day. These fish feed on crabs, shrimps, sea snails, and worms.