Distinctive Characters: Dorsal fin with 9 spines and 12 rays. Anal fin with 3 spines and 12 rays. Pectoral fin with 13 rays. Body depth 3.5-4.1 in standard length. - First two dorsal spines close together, prolonged in males. Caudal fin slightly emarginate. Pelvic fin short. Preopercle with a membranous flap at angle, the margin above it usually finely serrate for about half its length.
Colour: Females lavender-grey. The centres of scales darker than edges. Head behind the eye partially blue green. A large orange red spot covering pectoral fin base. Males light blue-green on dorsal three fifths of body, densely spotted with vertically elongated small black spots. In Maldivian specimens, posterior part of back appears orange.
Habitat and Biology: Occurs in aggregations usually on outer reef slopes. The females greatly outnumber the males. Feeds on zooplankton.
Distribution: Maldives to Western Pacific.
Remarks: Pseudocoris yamashiroi is common on the deeper part of outer reef slopes. Despite this, and its active swimming behaviour it is easily overlooked because of its relatively small size and rather dull colouration. Maldivian males differ from those in the Western Pacific in having orange, rather than green, on the posterior part of the back.