Family:  Acanthuridae

Scientific name: Acanthurus leucosternon    Common name: Powder Blue Tang

Distribution: Tropical Indo-Pacific Seas.

Food: Algae and other vegetable/dried food. Frozen Mysis shrimp etc.


The Powder Blue is oval shaped with a very compressed body. The small mouth is armed with fine teeth ideal for browsing on algae. The pectoral fins are long, rounded white ventral fins are also long and and there is a shallow notch in the caudal fin.

As with most Tangs the caudal peduncle is armed with a very sharp scalpel-like spine which lays flat against the fish's body and can be flicked out for use when threatened.

The body colour of the fish is a beautiful powder blue (hence the name) and it has a black mask on the face; there is a white patch from the throat to the base of the pectoral fin.
The jaws are dark, separated from the black mask by a thin white band.
The dorsal fin is brilliant yellow with a light edge. The caudal peduncle is also yellow, as is the "scalpel"' spine. The caudal fin has two dark, oblique stripes and a blue bar at the end.


Normally sold in aquatic outlets at about 3 long but they will eventually grow up to 11.75 inches.

Sexual differences


Water requirements

Temperature between 77-84oF (25-29oC) pH between 8.2 and 9.4 with a density of between 1020 and 1024. Good illumination is preferred and a large tank (6ft+) with a substrate of coral sand.


This is an active fast moving fish that is always on the move. As you'll see from the photo below the Powder Blue Tangs form huge and impressive shoals on the hunt for food.

It swims with a strange bobbing motion and needs plenty of space.




Keep only single individual in a tank and take care in associating it with other fishes in the tank.


Eats algae and small creatures. Enchytraea, Mussel flesh, Mysis shrimps and will acclimatise to a variety of animal, vegetable and dried foods in the aquarium.

This article first appeared in the Newsletter of Dunstable & D.A.S.


by Martin Kelly
Dunstable & District A.S.

Last updated February 2007