Also known as Bleeker´s Surgeonfish, Blue-lined Surgeonfish, Doctorfishes, Elongate Surgeon, Elongate Surgeonfish, Elongate Tang, Elongated Surgeonfish, Lancetfishes, Mata Surgeonfish, Mata Tang, Pale Surgeon, Pale Surgeonfish, Striped Surgeon, Thorntailfish, Thorntails, Yellowmask.
Found in schools in murky waters over rocky bottoms along steep slopes of coral reefs.
They feed midwater on zooplankton.
Length - 50cm
Depth - 5-100m
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. (edit) Ref: https://www.fishbase.se/summary/Acanthurus-mata