Uncommon in the Solitary Islands Marine Park. Distributed throughout the Indo-Pacific region: from East Africa to the Tuamoto Islands, north to southern Japan, south to Australia and Tonga. In Australia recorded offshore reefs in north Western Australia, from the Coral Sea and Great Barrier Reef in Queensland south to central New South Wales and including Norfolk and Lord Howe Island.
Frequents lagoons and seaward reefs, usually with rich coral growths. Depth to at least 30 m.
Distinguished from similar Heniochus acuminatus by small horn on forehead, shorter first rays of dorsal fin and largely white and yellow anal fin rather than largely black. Juveniles often solitary, adults in pairs, especially during breeding. Feed on bottom dwelling invertebrates. Grows to 24 cm.
R. Stuart-Smith, G. Edgar, A. Green, I. Shaw, Tropical Marine Fishes of Australia. Reed New Holland Publishers, 2015. p.217.
Atlas of Living Australia website at https://bie.ala.org.au/search?q=heniochus+monoceros. Accessed 01/06/18.
FishBase. Froese, R. and D. Pauly. Editors. 2018. World Wide Web electronic publication. https://fishbase.ca/summary/Heniochus-monoceros.html. Accessed 01/06/18.