[7] Its body is compressed laterally, the first rays of its dorsal fin stretch in a long white filament.
The snout, spotted with black, is a bit stretched with a small terminal protractile (it can be extend) mouth.
The pennant coralfish can easily be confused with the quite similar schooling bannerfish, (Heniochus diphreutes ).
[8][9][10] The pennant coralfish lives in pairs and feeds on zooplankton in the water column, coral polyps and occasionally benthic invertebrates.
[2] The pennant coralfish was first formally described as Chaetodon acuminatus in 1758 by Linnaeus in the 10th edition of Systema Natura.