Cucumber Pearlfish, Onuxodon margaritiferae (Rendahl 1921)

Other Names: Cucumber Fish, Pearlfish

Cite this page as:

Bray, D.J. 2026, Onuxodon margaritiferae in Fishes of Australia, accessed 05 Jun 2026, https://fishesofaustralia.net.au/home/species/2874

Cucumber Pearlfish, Onuxodon margaritiferae (Rendahl 1921)

More Info

Depth	commensal with pearl oysters
Distribution	Trimouille Island, Western Australia, to Ashmore Reef in the Timor Sea, around the tropical north to Cronulla, New South Wales, including reefs in the Coral Sea. The species is commensal in the mantle cavity of pearl oysters (Pinctada spp.) and other large bivalve molluscs, and in holothurians.
Features	Body eel-like, shallow to moderate in depth, trunk compressed; 1 to several large symphyseal fangs on premaxilla and dentary; anterior swim bladder modified into 'rockerbone'; predorsal bone present; pectoral fin rays supported by numerous small distal radials. Precaudal vertebrae 18-20.
Feeding	Feeds on crustaceans and polychaetes.
Biology	An endocommensal species, commonly found within the mantle cavity of oysters: the Australian Pearl Oyster, Giant Rock Oyster (Pycnodonta hyotis), Penguin's Wing Oyster (Pteria penguin), and other large bivalves, including clams. Individuals often form sexual pairs within the host species.
Fisheries	May be taken as bycatch in prawn trawl fisheries.
Etymology	The specific name is from the Latin margarita (= pearl) and –fer (= to have, to bear), as specimens are found in the mantle of large pearl-bearing bivalves.
Species Citation	Fierasfer margaritiferae Rendahl 1921, Kongliga Svenska Vetenskaps-Academiens Nya Handlingar, Stockholm 61(9): 5, Fig. 2. Type locality: 45 nautical miles west-southwest of Cape Jaubert, northwestern Australia, depth 70 feet.
Author	Bray, D.J. 2026
Resources	Atlas of Living Australia Australian Faunal Directory Catalog of Fishes

Cucumber Pearlfish, Onuxodon margaritiferae (Rendahl 1921)

References

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

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.

Arnold, D.C. 1956. A systematic revision of the fishes of the teleost family Carapidae (Percomorphi, Blennioidea), with descriptions of two new species. Bulletin of the British Museum (Natural History) Historical Series 4(6): 245-307 figs 1-20

Coleman, N. 1980. Australian Sea Fishes South of 30ºS. Lane Cove, NSW : Doubleday Australia Pty Ltd 309 pp.

Ho, H. 2020. Onuxodon margaritiferae. The IUCN Red List of Threatened Species 2020: e.T135445122A137454776. https://dx.doi.org/10.2305/IUCN.UK.2020-1.RLTS.T135445122A137454776.en. Accessed on 06 February 2026.

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

Markle, D.F. & Olney, J.E. 1990. Systematics of the pearlfishes (Pisces: Carapidae). Bulletin of Marine Science 47(2): 269-410

Nielsen, J.G., Cohen, D.M., Markle, D.F. & Robins, C.R. 1999. Ophidiiform Fishes of the World. An annotated and illustrated catalogue of pearlfishes, cusk-eels, brotulas and other ophidiiform species known to date. FAO Fisheries Synopsis No. 125 Vol. 18. 178 pp.

Olney, J.E. & Markle, D.F. 1986. Family No. 97: Carapidae. pp. 350-354 in Smith, M.M. & Heemstra, P.C. (eds). Smith's Sea Fishes. Johannesburg : Macmillan South Africa xx + 1047 pp. 144 pls.

Rendahl, H. 1921. Results of Dr. E. Mjöberg's Swedish Scientific Expeditions to Australia 1910–13. 28. Fische. Kongliga Svenska Vetenskaps-Academiens Nya Handlingar, Stockholm 61(9): 1-24 figs 1-7

Williams, J.T. 1984. Synopsis and phylogenetic analysis of the pearlfish subfamily Carapinae (Pisces: Carapidae). Bulletin of Marine Science 34(3): 386 - 397.