Freshwater Moray, Gymnothorax polyuranodon (Bleeker 1853)

Other Names: Blackspotted Moray, Manytoothed Moray, Spotted Freshwater Moray, Spotted Freshwater Moray Eel

A Freshwater Moray, Gymnothorax polyuranodon, at Mareeba, Queensland, November 2018. Source: coenobita / License: CC by Attribution-NonCommercial

A yellowish to brownish moray patterned with large dark irregular spots and blotches, 5-7 streaks or rows of spots on the head, and a pale yellowish snout and lower jaw. The dorsal fin is fleshy and originates behind the gill opening.

Cite this page as:
Bray, D.J. & Gomon, M.F. 2019, Gymnothorax polyuranodon in Fishes of Australia, accessed 25 May 2024,

Freshwater Moray, Gymnothorax polyuranodon (Bleeker 1853)

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Known in Australia from seven catchments in the Wet Tropics region of northeast Queensland between Noah Creek and the North Johnstone River, including Cooper Creek, Daintree River, Endeavour River, Mowbray River, Mulgrave River, Harvey Creek (Russell River catchment), Noah Creek and North Johnstone River. Elsewhere the species occurs in the tropical Indo-West Pacific: Sri Lanka, Indonesia, Borneo, New Guinea, Philippines, New Caledonia and Fiji.

Found in freshwater, estuarine and marine habitats, often in the lower reaches of freshwater streams, usually within 20-30 km of the sea. In Queensland, the Freshwater Moray was found in freshwater streams year-round, preferring pools with large boulders.


Vertebrae 226
Body elongate, firm, muscular and compressed; dorsal profile of head above and behind eye raised by strong head muscles; eyes well developed; jaws equal; anterior nostril tubular, near tip of snout; posterior nostril high on head near eye; mouth large, gape extends beyond posterior margin of eye; lips without fleshy flange; jaw teeth strong; gill opening a small round slit at midside; lateral line pores absent on body except for 1 or 2 above and before gill opening.
Scales absent, covered in skin.
Dorsal fin begins over or slightly behind gill opening, concealed by thick skin and sometimes difficult to see; dorsal, anal and caudal fin confluent; pectoral and pelvic fins absent.


Adults tan with large, irregular, brown spots forming longitudinal streaks on head; snout an lower jaw pale. Juveniles more or less uniform grey.


Nocturnal predators, feeding on fishes and a variety of invertebrates including crabs, shrimps and octopuses.

Species Citation

Muraena polyuranodon Bleeker, 1853, Nat. Tijdschr. Ned. Ind. 5: 248. Type locality: Ceram, Indonesia.


Bray, D.J. & Gomon, M.F. 2019


Atlas of Living Australia

Freshwater Moray, Gymnothorax polyuranodon (Bleeker 1853)


Allen, G.R. Field guide to the freshwater fishes of New Guinea. Publication, no. 9. Christensen Research Institute, Madang, Papua New Guinea, 268 pp.

Allen, G.R., Midgley, S.H. & Allen, M. 2002. Field Guide to the Freshwater Fishes of Australia. Western Australian Museum. 394 pp.

Bleeker P. 1853. Derde bijdrage tot de kennis ichthyologische fauna van Ceram. Nat. Tijdschr. Ned. Ind. 5: 233-248. See ref at BHL

Bohlke, E.B. & McCosker, J.E.. 2001. The moray eels of Australia and New Zealand, with the description of two new species (Anguilliformes: Muraenidae). Records of the Australian Museum 53(1): 71-102.

Böhlke, E.B., McCosker, J.E. & Smith, D.G. 1999. Family Muraenidae, In Carpenter, K. E. & V. H. Niem. Species identification guide for fisheries purposes. The living marine resources of the western central Pacific. Batoid fishes, chimeras and bony fishes part 1 (Elopidae to Linophrynidae). FAO, Rome.

Ebner, B.C., Fulton, C.J.,  Donaldson, J.A. & Schaffer, J. 2015. Distinct habitat selection by freshwater morays in tropical rainforest streams. Ecology of Freshwater Fish doi: 10.1111/eff.12213 Abstract

Ebner, B.C., Kroll, B., Godfrey, P., Thuesen, P.A., Vallance, T., Pusey, B., Allen, G.R., Rayner, T.S. & C.N. Perna. 2011. Is the elusive Gymnothorax polyuranodon really a freshwater moray? Journal of Fish Biology 79(1): 70–79. doi:10.1111/j.1095-8649.2011.02987.x. Abstract

Mailautoka, K. & McCosker, J. 2012. Gymnothorax polyuranodon. The IUCN Red List of Threatened Species. Version 2015.2. . Downloaded on 05 September 2015.

Monkes, N. 2006. Chapter .Freshwater morays and other eels, pp. 220–251 in Monkes, N. (ed.) Brackish-Water Fishes: An Aquarist's Guide to Identification, Care & Husbandry. Neptune City, New Jersey : T.F.H. Publications 384 pp.

Quick Facts

CAAB Code:37060067

Conservation:IUCN Least Concern

Depth:0-5 m

Fishing:Aquarium fish

Habitat:Freshwater (marine larvae)

Max Size:150 cm TL

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CAAB distribution map