This species resembles Heniochus monoceros in size and shape, but differs in several aspects of coloration. The white tall dorsal fin extends from the most posterior white band on the body and the black and white bands are not sharply delineated, fading into each other at the borders. Also, a portion of the anal fin of H. monoceros is yellow, but it is all white and black in H. singularis. This is apparently a very rare species at Kwajalein. We have recognized only about six specimens, one pair, one by itself and three of them hanging out with different individuals or small groups of H. monoceros. Five were on lagoon pinnacles and one on a lagoon bottom shipwreck. They may be more common, but you have to look a little closely to notice they are not just H. monoceros.
Heniochus singularis is fairly common at Pohnpei (photo below), about a thousand kilometers west of Kwajalein.
Created 15 October 2010
Updated 18 March 2021