Phantom bannerfish

Scientific name : Heniochus pleurotaenia

Medium size butterfly fish (19 cm), raised dorsal fin, side with an incomplete white band between ventral and anal fins. Adults with horns above the eyes and a striking forehead knob. 
In lagoon and along the reef front and external reef, in areas rich of coral, its main food. It feeds also on other benthicinvertebrates. 
Easily distinguished from other Heniochus, and in particular from Heniochus varius of the Pacific Ocean, for the white band between ventral and anal fins.