The brilliant blue and yellow colors of the Blue Tang, or Palette Surgeonfish, make it one of the most distinctive and familiar of all reef fish. "Palette" in the name may refer to the black design with the circle, which loosely resembles an artist's palette. The adults are shy creatures, and may lodge themselves amongst the branches of hard corals when approached. Unfortunately this defensive habit sometimes leads to coral destruction, as unscrupulous fish collectors remove the entire coral from the reef. Identification:  Paracanthurus hepatus