Orange-shoulder Surgeonfish Acanthurus olivaceus

The Orange-shoulder Surgeonfish is also known as the Orange-bar Tang, the Orangespot, Orange-blotch and Orange-band. It is native to tropical reefs of the Indian and west Pacific Oceans.

The juvenile is bright yellow and develops an orange patch bordered with black on its "shoulder" and a darker last third.

In transition to adulthood, the subadult loses the yellow and takes on a white to olive colour, still with a lighter front two-thirds and darker hind.

The adult is grey (front) and black (back) with the orange bar. They can grow to some 25 cm long. They live in shoals on the reefs and feed on algae.