The Powder Blue Tang (Acanthurus leucosternon), commonly known as the blue surgeonfish or powder-blue surgeonfish, is a species of marine ray-finned fish belonging to the family Acanthuridae. It was first formally described in 1833 by the English naturalist Edward Turner Bennett. The specific name leucosternon combines the Greek words leukos meaning ‘white’ and sternon meaning ‘breast’, referring to the white chest shown by this species.

Physical Description

The Powder Blue Tang can reach an average size of 23 cm (9 in) in length. The body has an oval shape and is compressed laterally. Like other surgeonfishes, it swims with its pectoral fins. The caudal fin has a crescent shape. The fish has a ‘surgeon’s scalpel’, an erected part of the spine located at the base of the tail. The mouth is small and pointed in a beak-like manner with tiny and sharp teeth. Its sides are blue, its dorsal fin and the base of the caudal fin are yellow, the head is black, the mouth, the throat area, the anal and pelvic fins are white. The pectoral fins are transparent with yellow reflections. The intensity of its blue color shows off if the fish is healthy or not. The fish does not undergo color changes as it matures.

Distribution and Habitat

The Powder Blue Tang is found in tropical waters from the Indian Ocean. The species inhabits shallow and clear coastal waters always associated with a reef. It prefers flat top reefs and areas along seaward slopes.

Diet and Feeding

The Powder Blue Tang is herbivorous, eating mostly benthic algae. It has a diurnal activity. It is solitary, territorial and aggressive with other surgeonfish. In cases where food is plentiful, it may feed in shoals, but in cases of scarcity, it may compete individually for food. It may use its surgeon’s scalpel as a defensive weapon.

Aquarium Care

The Powder Blue Tang is a commonly sold fish that is moderately difficult to care for. It requires a large, well-established aquarium with excellent water quality. It is reef safe and is compatible with most species except other species of fish in the genus Acanthurus.

Conservation Status

Classified as Least Concern by the IUCN Red List.