Also known as Blue-banded Surgeon, Blue-banded Surgeonfish, Blue-lined Surgeonfish, Clown Surgeon, Clown Surgeonfish, Clown Tang, Doctorfish, Lancetfish, Lined Surgeon, Lined Surgeonfish, Pyjama Clown, Striped Surgeon, Tang Clown, Thorntail, Thorntail Fish.
Found singly, harems over shallow reef flats, slopes and gutters usually exposed to surge currents.
They feed on algae and crustaceans.
Small juveniles secretive among rubble boulders.
Length - 35cm
Depth - 1-15m
Surgeonfish have a blade like spine in the tail that points outwards when bent, unicorns have two hook-like plates along the tail, these are used for defence and are as sharp as a surgeons scalpel, hence the name "Surgeonfish".
Some species are venomous. Ref: http://www.fishbase.org/summary/Acanthurus-lineatus.html