Two-lined Monocle Bream

Scolopsis bilineata is a species of threadfin bream native to the Indian Ocean and the western Pacific Ocean. This species is sought-after by local peoples for food and can also be found in the aquarium trade.

Description

This species can reach a length of 25 cm (9.8 in), though most only reach a length of around 13 cm (5.1 in).

Color is purpulish dark grey on head and back with diagonal black-edged white-yellow band separating dark area from the rest of the mainly whitish body. There is a white blotch below posterior dorsal fin. It has 3 yellow stripes on upper head. Juveniles are with alternating black and yellow stripes on the upper half and whitish below, Batesian mimic of the poison-fanged blenny Meiacanthus grammistes.

Dorsal spines (total): 10; Dorsal soft rays (total): 9; Anal spines: 3; Anal soft rays: 7. This species is distinguished by the following characters: head scales reaching to or just in front of anterior nostrils; lateral line scales 43-47 (usually 45-46); pectoral fin rays 16-18 (usually 17); snout length less than eye diameter; greatest body depth 2.5-3.0 in SL.

The two-lined monocle bream exhibits biofluorescence, that is, when illuminated by blue or ultraviolet light, it re-emits it as green, and appears differently than under white light illumination (only stripes on the upper front part are visible). Biofluorescence may assist in intraspecific communication and camouflage, blending the fish with green-fluorescing Acropora corals.

Distrubution

Indo-West Pacific: Maldives and the Laccadive Islands to Fiji, north to southern Japan, south to Lord Howe Island.

Habitat

An inhabitant of coral reefs, this species can be found at depths from 1 to 25 m (3.3 to 82.0 ft). They are carnivorous, preying on smaller fishes, as well as benthic invertebrates.