Distinctive Characters: Dorsal fin with 10-12 spines and 32-36 rays. Anal fin with 2 spines and 29-33 rays. Pectoral rays 11-13. Segmented caudal rays 11. Body depth 6.6-8.0 in standard length. Snout conical. Mouth ventral. Lower jaw with a pair of long curved canines. Dorsal fin originates above hind margin of preopercle. Pelvic fin small, usually longer than eye diameter. Caudal fin emarginate.
Colour: Variable. Dark brown, yellowish brown, or yellow with two narrow bright blue stripes. Juveniles have a single upper blue stripe. Median fins yellowish in both forms.
Habitat and Biology: Inhabits reef edge and slope. Feeds by rapid attacks on other fishes, removing dermal tissue, mucus, and sometimes scales.
Distribution: Indo-Pacific except Hawaii.
Remarks: Plagiotremus rhinorhynchos, in the blue black-stripe phase mimics the cleaner wrasse, Labroides dimidiatus. In the yellow phase it approximates the colour of common, harmless scalefin anthias, Pseudanthias squamipinnis. In this disguise it get closer enough to attack other fishes. Previously recorded under the genus Runula.