Harlequin Filefish, Oxymonacanthus longirostris (Bloch & Schneider 1801)

Other Names: Beaked Leatherjacket, Beaked Leather-jacket, Coral Filefish, Longnose Filefish, Long-nose Leatherjacket, Longnosed Filefish, Orange Spotted Filefish

A Harlequin Filefish, Oxymonacanthus longirostris, at Mary Island, Solomon Islands. Source: Sally Polack / FishWise Professional. License: CC BY Attribution-Noncommercial-ShareAlike


A small slender greenish leatherjacket with rows of yellow spots and dashes along the sides and a small black blotch on the tail. Males have bristles on the tail base.

Harlequin Filefish shelter amongst branches of Acropora corals at night. They not only resemble coral branches, but they smell like one too (Brooker et al. 2014) - enabling the filefish to remain undetected by nocturnal predators.

Video of Harlequin Filefish spawning in a home aquarium.

Cite this page as:
Bray, D.J. 2018, Oxymonacanthus longirostris in Fishes of Australia, accessed 01 Dec 2021, https://fishesofaustralia.net.au/home/species/812

Harlequin Filefish, Oxymonacanthus longirostris (Bloch & Schneider 1801)

More Info


Widespread in tropical and subtropical waters of eastern and western Australia, from the Houtman Abrolhos islands to the Dampier Archipelago, Western Australia, including offshore reefs, Ashmore Reef, Timor Sea, and the far northern Great Barrier Reef and reefs in the Coral Sea, to Moreton Bay, Queensland; also Christmas Island in the eastern Indian Ocean, and Lord Howe Island in the Tasman Sea.

Elsewhere the species occurs in the Indo-west Pacific. Inhabits lagoons and seaward reefs in depths of 1-35 m.


Dorsal fin: II (2nd spine not visible), 31-35; Anal fin: 29-32


An obligate coralivore - feeding entirely on polyps of Acropora corals.


Forms monogamous pairs.


Although traded in the aquarium industry, Harlequin Filefish are very difficult to maintain in captivity. In the wild, this species feeds only on the polyps of Acropora corals.


The Harlequin Filefish has been listed as Vulnerable on the IUCN Red List of Threatened Species because it depends solely on Acropora corals for food, and is therefore highly susceptible to habitat loss due to coral bleaching.


Species Citation

Balistes hispidus longirostris Bloch & Schneider 1801, Systema Ichthyologiae :464 (as Balistes hispidus var. longirostris). Type locality: East Indies.


Bray, D.J. 2018


Australian Faunal Directory

Harlequin Filefish, Oxymonacanthus longirostris (Bloch & Schneider 1801)


Allen, G.R. 1997. Marine Fishes of Tropical Australia and South-east Asia. Perth : Western Australian Museum 292 pp. 106 pls.

Allen, G.R. & Erdmann, M.V. 2012. Reef fishes of the East Indies. Perth : Tropical Reef Research 3 vols, 1260 pp.

Allen, G.R. & Steene, R.C. 1988. Fishes of Christmas Island Indian Ocean. Christmas Island : Christmas Island Natural History Association 197 pp.

Allen, G.R., Steene, R.C. & Orchard, M. 2007. Fishes of Christmas Island. Christmas Island : Christmas Island Natural History Association 2 edn, 284 pp.

Allen, G.R. & Swainston, R. 1988. The Marine Fishes of North-Western Australia. A field guide for anglers and divers. Perth, WA : Western Australian Museum vi 201 pp., 70 pls.

Barlow, G.W. 1987. Spawning, eggs and larvae of the longnose filefish Oxymonacanthus longirostris, a monogamous coralivore. Environmental Biology of Fishes 20(3): 183-194.

Bleeker, P. 1853. Derde bijdrage tot de kennis der ichthyologische fauna van Amboina. Natuurkundig Tijdschrift voor Nederlandsch Indië 4: 91-130 (as Monacanthus chrysospilos)

Bloch, M.E. & Schneider, J.G. 1801. Systema Ichthyologiae Iconibus ex Illustratum. Berlin 584 pp. 110 pls.

Brooker, R.M., P.L. Munday, S.J. Brandl & G.P. Jones. 2014. Local extinction of a coral reef fish explained by inflexible prey choice. Coral Reefs 33: 891–896. DOI 10.1007/s00338-014-1197-3

Brooker, R.M., P.L. Munday, D.P. Chivers & G.P. Jones. 2014 You are what you eat: diet-induced chemical crypsis in a coral-feeding reef fish. Proceedings of the Royal Society B: DOI: 10.1098/rspb.2014.1887

Francis, M. 1993. Checklist of the coastal fishes of Lord Howe, Norfolk, and Kermadec Islands, southwest Pacific Ocean. Pacific Science 47(2): 136-170 figs 1-2

Hutchins, J.B. 1986. Monacanthidae. In, Smith, M.M. & Heemstra, P. (eds). Smith's Sea Fishes. Johannesburg : Macmillan South Africa xx + 1047 pp. 144 pls.

Hutchins, J.B. 1994. A survey of the nearshore reef fish fauna of Western Australia's west and south coasts — The Leeuwin Province. Records of the Western Australian Museum, Supplement 46: 1-66 figs 1-6

Hutchins, J.B. 2001. Biodiversity of shallow reef fish assemblages in Western Australia using a rapid censusing technique. Records of the Western Australian Museum 20: 247-270.

Hutchins, J.B. 2001. Monacanthidae. pp. 3929-3947 in Carpenter, K.E. & Niem, T.H. (eds). The Living Marine Resources of the Western Central Pacific. FAO Species Identification Guide for Fisheries Purposes. Rome : FAO Vol. 6 pp. 3381-4218.

Hutchins, B. 2004. Fishes of the Dampier Archipelago, Western Australia. Records of the Western Australian Museum, Supplement 66: 343–398.

Hutchins, J.B., Williams, D.McB., Newman, S.J., Cappo, M. & Speare, P. 1995. New records of fishes for the Rowley Shoals and Scott/Seringapatam Reefs, off north-western Australia. Records of the Western Australian Museum 17: 119-123.

Johnson, J.W. 2010. Fishes of the Moreton Bay Marine Park and adjacent continental shelf waters, Queensland, Australia. pp. 299-353 in Davie, P.J.F. & Phillips, J.A. Proceedings of the Thirteenth International Marine Biological Workshop, The Marine Fauna and Flora of Moreton Bay. Memoirs of the Queensland Museum 54(3)

Kokita T. & Nakazono A. 1999. Pair territoriality in the longnose filefish, Oxymonacanthus longirostris. Ichthyological Research 46: 297-302.  

Kokita T. & Nakazono A. 2001. Rapid response of an obligately corallivorous filefish Oxymonacanthus longirostris (Monacanthidae) to a mass coral bleaching event. Coral Reefs 20: 155-158.

Kuiter, R.H. 1996. Guide to sea fishes of Australia. A comprehensive reference for divers and fishermen. Sydney, NSW, Australia : New Holland Publishers xvii, 434 pp.

Larson, H.K., Williams, R.S. & Hammer, M.P. 2013. An annotated checklist of the fishes of the Northern Territory, Australia. Zootaxa 3696(1): 1-293.

Marshall, T.C. 1964. Fishes of the Great Barrier Reef and Coastal Waters of Queensland. Sydney : Angus & Robertson 566 pp. 136 pls.

Matsuura, K. 2015. Taxonomy and systematics of tetraodontiform fishes: a review focusing primarily on progress in the period from 1980 to 2014. Ichthyological Research 62: 72-113.

Matsuura, K. & Motomura, H. 2016. Oxymonacanthus longirostris (errata version published in 2017). The IUCN Red List of Threatened Species 2016: e.T70010721A115476659. http://dx.doi.org/10.2305/IUCN.UK.2016-1.RLTS.T70010721A70011814.en. Downloaded on 29 October 2018.

Michael, C. 1999. Marine Fishes. 500+ Essential-To-Know Aquarium Species. Microcosm Ltd.

Randall, J.E., Allen, G.R. & Steene, R. 1990. Fishes of the Great Barrier Reef and Coral Sea. Bathurst : Crawford House Press 507 pp. figs.

Randall, J.E., Allen, G.R. & Steene, R. 1997. Fishes of the Great Barrier Reef and Coral Sea. Bathurst : Crawford House Press 557 pp. figs.

Russell, B.C. 1983. Annotated checklist of the coral reef fishes in the Capricorn-Bunker group, Great Barrier Reef, Australia. Great Barrier Reef Marine Park Authority. Special Publication Series 1: 1-184 figs 1-2

Russell, B.C., Larson, H.K., Hutchins, J.B. & Allen, G.R. 2005. Reef fishes of the Sahul Shelf. The Beagle, Records of the Museums and Art Galleries of the Northern Territory Supplement 1 2005: 83-105

Swainston, R. 2011. Swainston's Fishes of Australia: The complete illustrated guide. Camberwell, Victoria : Penguin Australia 836 pp.

Whiteman, E.A. & Côté, I.M. 2004. Monogamy in marine fishes. Biological Reviews 79: 351-375.

Quick Facts

CAAB Code:37465062

Conservation:IUCN Vulnerable

Depth:1-35 m

Feeding:Feeds only on coral polyps

Fishing:Aquarium fish (difficult)

Max Size:12 cm TL

Max Size:Reef associated

Species Image Gallery

Species Maps

CAAB distribution map