Distinctive Characters: Dorsal fin with 10 spines and 13-15 rays. Anal fin with 3 spines and 13-16 rays. Pectoral rays 17-20. Body depth 2.5-2.9 in standard length. Well compressed body. Mouth nearly vertical, snout long. Posterior and lower margins of preopercle finely serrated. Caudal fin emarginate. Colour: Usually uniform red to deep red with a series of about 15 small dark spots along lateral line. Median and pelvic fins dusky red. A black spot at base of first 3 pelvic rays. Capable of quickly altering to pinkish silver with six red bars on body and one extending ventrally from eyes.
Habitat and Biology: Known from the depth range about 15 to at least 250 m. Easily approached underwater. Sometimes seen in small groups. Nocturnal. Feeds primarily on the larger zooplanktons.
Distribution: Indo-Pacific.
Remarks: Piracanthus hamrur is a common inhabitant of Maldivian reefs. This species is closely related to the endemic P. meeki Jenkins of Hawaii and the Atlantic P. arenatus Cuvier.