A colourful tropical marine fish,
with the scientific name Acanthurus leucosternon. It is mainly greyish-blue,
with for the most part a yellow dorsal fin, a black face with a rather large
eye, a white mouth and chin (or upper breast), and white ventral and anal fins,
while the pectoral fins are transparent with a yellow reflection, and the tail
white and black. The name surgeonfish derives from two hard spines at the base
of its tail, one spine on each side of the body, that lie flat in a groove and
which are as sharp as a surgeon's scalpel. When the fish is provoked or feels
threatened, these spines can be used as a defensive weapon, as when the fish
flips its tail, the spines pop out like small scalpel-like knives. This fish
lives solitary or in small groups and dwells most of its time in shallow waters.
It is herbivorous, feeding mainly on algae that grows on rocks, and as such is
commonly found in shallow rocky shores, or exposed coral reefs. It is
also called Powderblue Tang and in Thai it is known as pla khih tang bet fah ok
which translates as ‘white-breasted blue hook tang fish’. Also spelled Powder
also POSTAGE STAMPS.