Halichoeres marginatus, the Dusky Wrasse, reaches a maximum total length of 18 cm (7 inches). Its body is elongated and moderately compressed. Males display a greenish to brownish coloration, marked by narrow blue stripes or rows of blue spots along their sides. The pectoral fin features a broad yellow margin with blue submarginal spots, and the tail base is distinguished by a greenish crescent-shaped band. Females are brown with darker, narrow stripes along their sides, a prominent black ocellus positioned centrally on the dorsal fin, and a greenish margin on the caudal fin. Juveniles are predominantly blackish to dark brown, exhibiting narrow white lateral stripes, a bluish to black ocellus on the dorsal fin, and white blotches on the back. The scientific name Halichoeres combines Greek words for "sea" and "to go," referring to the genus's active foraging behaviour across reefs.
The Dusky Wrasse inhabits reef-associated environments, preferring areas with mixed sand, rubble, and scattered live coral heads. It occurs at depths from 1 to 30 meters (3 to 98 feet). This species is diurnal and typically observed foraging solitarily or in small groups over the substrate. Its diet primarily consists of small benthic invertebrates, including crustaceans, molluscs, and foraminifera. At night or when threatened, it burrows into sandy patches to hide.
Halichoeres marginatus is a protogynous hermaphrodite, with individuals developing initially as females and later transitioning to males. Spawning occurs in pairs or groups, releasing pelagic eggs into the water column.
Why it's threatened
There are no major threats to this species, although it is collected for the aquarium trade in some localities.
Threat classification from the IUCN Red List.
