Also known as Blacktongue Unicorn, Blacktongue Unicornfish, Bluetail Unicornfish, Doctorfish, Lancetfish, Nohorn Unicorn, Sleek Unicorn, Thorntail, Thorntail Fish, Thorpe's Unicornfish.
Found in large schools over reef slopes in clear lagoons and seaward reefs.
They feed on filamentous red algae and zooplankton comprising crab larvae, arrow worms and pelagic tunicates.
Length - 75cm
Depth - 6-150m
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/1263