Description

Also known as Arabian Surgeonfish, Arabian Tang, Clown Surgeonfish, Clown Tang, Doctorfish, Lancetfish, Red Sea Clown, Red Sea Clown Surgeon, Red Sea Surgeonfish, Sohal Tang, Thorntail, Thorntail Fish, Zebra Surgeonfish, Zebra Tang.

Found singly or in schools, fiercely territorial, over exposed surge zones, along edges of seaward reefs.
They feed on algae.
Length - 40cm
Depth - 0-20m
Western Indian Ocean - Red Sea to Persian Gulf

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-sohal