This is the largest of the bannerfish at Kwajalein. It is not all that common, but hard to miss due to its larger size and usually exposed position. Often pairs can be found hanging around or under large table Acropora colonies on the upper flat portion of the seaward reef, but the can also be found on lagoon and pinnacle reefs. Rarely, these are seen in small groups. It is similar in size and shape to Heniochus singularis, but in H. monoceros the black bands (especially the middle one) tend to be more solid black and the white dorsal fin is an extension of the second to the last white band on the body. They also have yellow coloration on the anal fin that is lacking in H. singularis. They are reported to eat mostly benthic invertebrates.
Created 15 October 2010