Latin name

Cephalopholis argus

Other name

Roi, bluespotted grouper, and celestial grouper.

Identification

The body of the peacock hind is elongated, massive, somewhat compressed at the sides, cylindrical in shape, covered on the sides with ctenoid scales. Its height is 2.7-3.2 times the standard length. The length of the head exceeds the height of the body and is 2.4-2.7 times shorter than the body length. The interorbital space is flat or slightly convex. Eyes small, their diameter considerably less than the length of the snout. The forewing is rounded, with serrated edges in juveniles, smooth in adults, and the lower edge is fleshy. The upper jaw is covered with scales, the tip of which extends well beyond the vertical line running through the posterior margin of the eye. There are 9-11 gill stamens on the upper part of the first gill arch and 17-19 gill stamens on the lower part. Both jaws have small fang-like teeth in the anterior part, and there are teeth on the scutellum. There are 46-51 scales on the lateral line. There are 95-110 rows of scales along the lateral line, the scales on the sides of the body are coarse with a few additional scales.

Features of fish fins

Dorsal spines (total): 9; Dorsal soft rays (total): 15 - 17; Anal spines: 3; Anal soft rays: 9. 

The dorsal fin has 10 hard and 15-17 soft rays; there are no elongated rays. The membranes between the hard rays are truncated. The anal fin has 3 hard and 9 soft rays. Pectoral fins have 16-18 soft rays. The pelvic fins are shorter than the pectoral fins, their ends do not reach the anus. The caudal fin is rounded. 

Fish colouring

The body and head of the Peacock Hind is dark brown, covered with numerous small blue eye-shaped spots with a black border. There are 5-6 pale cross-stripes along the back of the body. There is a large pale area on the thorax. Posterior margin of pectoral and pelvic fins usually with a narrow white border. Distal margins of pectoral fins sometimes dark chestnut brown. Tops of truncated dorsal fin membranes golden orange.

Distribution

Specimens have been found from the Red Sea to southern Africa, along the coast of south and south-east Asia and further east to French Polynesia and the Pitcairn Islands. In the Pacific Ocean as far north as Japan and as far south as Australia (Lord Howe Island). Introduced into the Hawaiian Islands.

Habitat

Marine, tropical, reef-dwelling species. Depth range 0 to 40 m. Adults inhabit benthic and benthopelagic in a variety of coral habitats from tide pools to depths of at least 40 metres. They prefer the reef zone from 1 to 10 m. Juveniles live in shallow waters protected by coral thickets. 

Size

The maximum length of this species is 60 centimetres, but they are usually found at 40 centimetres.

Behavior

A widespread species that does not migrate. Adults live in social groups of up to 12 adults, including 1 dominant male. Each group occupies a defined territory (up to 2000 square metres) defended by a territorial male and subdivided into secondary territories, each inhabited by a single female. Sometimes they may be solitary. 

Food and feeding habits

Adults feed mainly on fish (75-95%) and to a lesser extent on crustaceans. In the Red Sea they feed in the early morning and late evening, but in Madagascar they seem to feed more frequently at night. When hunting, they lie on the bottom and charge forward, preferring juvenile surgeonfish and crustaceans. Alternatively, they may hover motionless in the water column before attacking.

Reproduction

The male visits females daily, raising his dorsal fin to signal his approach. The female comes out of hiding and raises her own dorsal fin. They swim together, rubbing each other's sides before he leaves until the next day. In Micronesia, spawning is usually territorial and takes place at dusk. During courtship, both sexes become darker except for a keyhole-shaped white patch on the centre of the body.

Fishing

The species is important to artisanal fisheries throughout the Indo-West Pacific region and is commonly caught by hook and line, spear and trap.

Relationship with a person

This fish can be found in live fish markets in Hong Kong. There have been reports of ciguatera poisoning.