About Stethojulis trilineata (Bloch & Schneider, 1801)
Stethojulis trilineata is a small species of wrasse that can reach a total length of 15 centimetres (5.9 inches). Initial phase (female) individuals are greenish to brownish-grey, with numerous whitish spots on their upper flanks and a dark spot on the caudal peduncle. Terminal phase (male) individuals have three thin, pale pink stripes running along their body, plus a fourth stripe that starts on the head and extends to the area above the pectoral fin. This species has 9 spines and 11 soft rays in its dorsal fin, and 3 spines and 11 soft rays in its anal fin. Stethojulis trilineata has a wide distribution across the Indo-West Pacific. Its range extends from the Maldives east to Samoa and Palau, north to the Tokara Islands of Japan, and south to Montague Island in Australia. This wrasse inhabits clear-water reefs that are exposed to currents. It typically occurs in loose groups over reef crests and drop-offs, at depths up to 20 metres (66 feet). Spawning takes place in discrete pairs within the species' small groups, which usually number fewer than 15 individuals. Spawning can happen at any time of day, and does not appear to be affected by lunar or tidal cycles.