Also known as Doctorfish, Inshore Surgeon, Inshore Surgeonfish, Lancetfish, Northwest Surgeonfish, Ring-tailed Surgeonfish, Thorntail, Thorntail Fish.
Found singly or in small schools over shallow, protected, silty coastal reefs.
They feed on algae and plankton.
Length - 35cm
Depth - 2-90m
Widespread Western Pacific
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: https://www.fishbase.se/summary/Acanthurus-grammoptilus