The Orangeshoulder Tang (Acanthurus olivaceus), also known as the orange-shoulder surgeonfish or orangebar tang, is a species of marine ray-finned fish belonging to the family Acanthuridae. It is found in the Pacific Ocean and is popular in the marine aquarium trade.

Physical Description

The Orangeshoulder Tang has an oval-shaped, laterally compressed body. Juveniles are bright yellow. As they mature, the body coloration changes to olive-brown with a distinctive bright orange band or ‘shoulder’ mark behind the gill plate, which gives this species its common name. The dorsal fin has 9 spines and 25-27 soft rays while the anal fin has 3 spines and 23-25 soft rays. This species reaches a maximum total length of 35 cm (13.8 in).

Distribution and Habitat

The Orangeshoulder Tang is found in the Pacific Ocean from Hawaii to Japan, the Philippines, Indonesia, and the Great Barrier Reef. It inhabits shallow coral reefs and lagoons at depths between 2 and 30 meters.

Diet and Feeding

The Orangeshoulder Tang is herbivorous, grazing on benthic algae and filamentous algae. In captivity, it should be offered a varied diet including marine algae, spirulina, and high-quality vegetable-based preparations.

Aquarium Care

The Orangeshoulder Tang requires a spacious aquarium of at least 150 gallons with abundant live rock for grazing. It is semi-aggressive and may display territorial behavior toward other tangs. Generally considered reef-safe.

Conservation Status

Classified as Least Concern by the IUCN Red List.