Description
Dorsal spines (total): 10; Dorsal soft rays (total): 15-17; Anal spines: 3; Anal soft rays: 7-8 (usually: 7); Pectoral fins obtusely pointed, rays: 18-20; Lateral line scales: 48-52; Circumpeduncular scales: 25-27; Male caudal fin lunate, with elongated lobes, outer rays filamentous; Caudal concavity 19-35% in SL; Female caudal fin emarginate; Dorsal fin rays no elongated spines or rays, spinous and soft-rayed parts of equal height; Pelvic fins pointed with slight elongation of 2nd and 3rd rays, reaching between anus and 3rd anal fin spine; Scale rows between 5th dorsal fin spine and lateral line 2 or 3; Few auxiliary scales on head; Soft dorsal and anal fins scaly at base and along proximal part of inter-radial membranes; caudal fin scaly halfway to distal margin; Pectoral fins scaly over proximal half of fin; Pelvic fins with scales in rows on ventral side. Gill rakers: 8-11 + 22-28. Body depth: 2.8-3.2, head length: 3.1-3.4 in SL. Orbit diameter: 3.0-3.8, interorbital width: 3.9-4.3 in head length. Dorsal head profile slightly convex; Maxilla reaching vertical at centre of orbit, male maxilla with few irregular small serrae at lower rear edge; No papillae on rear edge of orbit. Villiform teeth in triangular patch on vomer and in narrow band on palatines. Preopercle vertical limb with 14-27 serrae, larger ventrally; Ventral limb smooth; Few small serrae on ventral edge of subopercle and on rear edge of interopercle. Nostrils subequal; Anterior nostril in short tube, rear margin with short flap not reaching slit-like rear nostril. Max. length: 14.0 cm TL. Depth range: 10 - 91 m, usually 10 - 60 m.

Color
Male: variable; Head, body and fins red, or pale reddish grey or almost white, with white streak from front of snout along lower edge of eye and across cheek to pectoral fin base; Often showing an irregular, vertically elongate scarlet blotch below lateral line at mid body; Silvery white streak running parallel with and just above lateral line also commonly seen; Caudal fin scarlet, with elongated upper and lowermost rays pale blue; Anal fin pale greenish yellow; Pelvic fins reddish.
Female: head and body reddish orange dorsally, body yellow-orange below lateral line; Ventral part of head white, with red spot on front end of lower jaw; Caudal fin red basally, rear margin wide, hyaline pale blue grey, with scarlet tip at each corner.

Etymology
Pseudanthias: from Greek, pseudes = false + from Greek, anthias = a name of an unknow fish given by Aristotle in "History of Animals". This book, written in the fourth century BC, is one of the major texts on biology by the ancient Greek philosopher Aristotle (384–322 BC), who had studied at Plato's Academy in Athens.
cooperi: named for Sir Clive Forster Cooper (1880–1947). He was an English palaeontologist and Director of the Cambridge University Museum of Zoology and Natural History Museum in London. In 1900, Forster Cooper travelled with John Stanley Gardiner to the Maldive and Laccadive Islands to undertake collections and study the formation of coral reefs.
Original description: Anthias cooperi Regan, 1902 - Type locality: Haddummati Atoll, Maldives, Indian Ocean, depth 40 fathoms.

Distribution

Indo-West Pacific: East Africa, Socotra, Seychelles, Madagascar and western Mascarenes east to Line Islands, Tonga and Samoa, north to Kagoshima Prefecture (southern Japan), south to Western Australia, New South Wales (Australia) and New Caledonia.

Biology
Mostly found on open substrate with low reef and remote bommies. Juveniles maybe shallow in coastal reefs. Form small, loose aggregations along current-swept drop-offs.

Similar species
Pseudanthias taeniatus (Klunzinger, 1884) - Reported from Red Sea; Northwestern Indian Ocean: Gulf of Aden.