Epibulus insidiator, the sling-jaw wrasse, is a spectacular coral reef fish that exhibits an extraordinary ability to protrude its jaws during feeding. This fish can rapidly protrude both upper and lower jaws to an extreme degree, extending the length of the head by 65% to capture evasive prey such as other fishes and small invertebrates. The sling-jaw is a member of the diverse and colorful fish family Labridae (the wrasses) and is closely related to the maori wrasses of the genus Cheilinus. The sling-jaw wrasse is among the most widely distributed coral reef fishes, occurring on coral reefs throughout the tropical Pacific from the Northwest Hawaiian Islands to the Western Pacific, Indian Ocean, and Red Sea.

One of the most widespread of wrasses, this species inhabits coral reefs of the Red Sea, Indian Ocean, and the entire Western and Central Pacific region, reaching Hawaii and the Tuamotu Archipelago to the east.

Diagnostic characters: Body moderately deep, maximum depth greater than length of head; dorsal profile of head convex in front of dorsal fin, a slight concavity above and before eye; head forming a broadly acute angle; jaws extremely protrusible, capable of being extended forward more then half the length of the head; 2 large canines situated anteriorly in each jaw; no enlarged tooth at rear of upper jaw; dorsal fin continuous, with 9 spines and 10 (rarely 11) soft rays, the spines and anterior soft rays of similar length; anal fin with 3 spines and 8 (rarely 9) soft rays; pectoral fins with 2 unbranched and 10 branched rays; pelvic fins filamentous in adults; caudal fin slightly rounded to truncate, the corners produced to form filamentous lobes in adults. Lateral line interrupted below posterior portion of dorsal fin, with a total of 22 or 23 pored scales. Scales reaching well onto bases of dorsal and anal fins; scales in front of dorsal fin extending forward to above eye; cheek and opercle scaled; lower jaw without scales.

Colour: overall brown or occasionally yellow; dorsal fin with several horizontal dark brown stripes and a black spot between first 2 spines; dark vertical bar on each scale; juveniles brown with several dark-edged, narrow, white bars and an ocellated black spot on anal fin and on rear of dorsal fin; large terminal phase males with whitish cheeks and nape, and reddish blotch of colour dorsally in front of dorsal fin origin.

• Marine

The sling-jaw is found on coral reefs of both exposed and protected areas to depths of 5-40m. It feeds upon small fishes, shrimps, and crabs which it can occasionally be seen capturing with its incredibly protrusive jaws. Large individuals are caught on hook and line, by spear, and are occasionally found in fish markets. The yellow phase is often captured for the aquarium trade, but fades to the more typical brown colour rendering it without commercial value.

The snout of the sling-jaw wrasse captures prey using multibar linkages to shoot its jaw out at high speed.