Cox's Gudgeon, Gobiomorphus coxii (Krefft 1864)

Other Names: Cox Gudgeon, Mulgoa Gudgeon, Nepean Gudgeon

Cox's Gudgeon, Gobiomorphus coxii, in the Nepean River, Douglas Park, New South Wales, Nov 2009. Source: Sascha Schultz / iNaturalist.org. License: CC by Attribution-NonCommercial

Summary:

A dark brown to greenish-brown gudgeon fading to pale brown or cream below, with blue, gold and yellow flecks on lower lateral scales, a dark midlateral stripe or series of midlateral blotches, a single black spot above pectoral fin base, two faint, dark stripes radiating from behind eye across gill cover, and 1-3 dark stripes on dorsal fins.

Cite this page as:

Martin F. Gomon, Gobiomorphus coxii in Fishes of Australia, accessed 21 Mar 2025, https://fishesofaustralia.net.au/Home/species/4143

Cox's Gudgeon, Gobiomorphus coxii (Krefft 1864)

More Info

Distribution	Endemic to eastern Australia from about Brisbane, Queensland, to Gippsland, Victoria. The species also occurs in the Swan River, Western Australia, where it is thought to have been introduced. Inhabits coastal and inland freshwaters to an altitude of about 700 m, usually in flowing, upland streams, including rapids. Juveniles often occur at lower altitudes, having been washed downstream as larvae. They migrate upstream during spring and summer, even managing to climb waterfalls and dam walls.
Features	Meristic features: Dorsal fin VI + I, 9; Anal fin I, 9; Caudal fin (segmented rays) 15; Pectoral fin 18-19; Pelvic fin I, 5; Gill rakers 9-12; Vertebrae 26-27. Body almost cylindrical; tapering and compressed posteriorly. Head large, snout bluntly rounded. Eyes moderately small, high on head near dorsal profile; interorbital narrow. Mouth oblique, upturned, of moderate size; just reaching anterior border of eye; jaws with bands of fine, pointed teeth. Lines of minute papillae across cheek and operculum, around preopercular margin and from each side of snout to above eye. Preopercular margin with 3-5 large pores. Body covered with ctenoid scales of moderate size forward to operculum and between eyes; lateral line absent, longitudinal series 36-40; cheeks naked; top of head with small scales to above back of eyes. Two separate dorsal fins; first rounded, notched between spines; second higher, slightly longer; anal fin opposite, smaller, and more rounded than second dorsal fin. Caudal fin moderately large, truncated. Pectoral fins large, rounded. Pelvic fins separate, thoracic; small, elongate, pointed.
Size	To around 19 cm SL, commonly to 15 cm, with females growing larger than males.
Colour	Dark brown to greenish-brown dorsally and laterally, fading to pale brown or cream ventrally; lower lateral scales flecked with blue, gold and yellow; single black spot above pectoral fin base; juveniles with series of mid-lateral, elongate blotches that merge to form single, broad, dark brown to black, mid-lateral stripe in older fish. Head dark brown; lower jaw and throat often black; 2 faint, dark stripes radiating from behind eye across operculum. Fins colourless to dusky-grey; dorsal fins with 1-3 dark stripes separated by areas of yellow or orange; fin margins often yellow; caudal fin with numerous dark spots forming irregular bands.
Feeding	Feeds on aquatic insects, crustaceans and small fishes.
Biology	Females lay their eggs on rocky surfaces and the male parent guards and fans the nest. The larvae hatch after 3-5 days, depending on water temperature, and are thought to be washed downstream to lowland rivers or estuaries.
Remarks	Capable of migrating up the wet surfaces of waterfalls and dams aided by their broad pectoral fins and pelvic fins which, when spread out, form a cup-shaped disc similar to pelvic fins of most gobies.
Species Citation	Eleotris coxii Krefft, 1864, Proc. Zool. Soc. Lond. 1864: 183. Type locality: upper Hawkesbury River, NSW, and a lagoon near Bronte, Sydney.
Author	Martin F. Gomon

Cox's Gudgeon, Gobiomorphus coxii (Krefft 1864)

References

Allen, G.R. 1989. Freshwater Fishes of Australia. Neptune, New Jersey : T.F.H. Publications 240 pp., 63 pls.

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

Cadwallader, P.L. & Backhouse, G.N. 1983. A Guide to the Freshwater Fish of Victoria. Melbourne : F.D. Atkinson Government Printer 249 pp. figs.

Cashner, R.C., Hawkes,G.P., Gartside, D.F. & Marsh-Matthews E. 1999. Fishes of the Nymboida, Mann and Orara Rivers of the Clarence River Drainage, New South Wales, Australia. Proceedings of the Linnean Society of New South Wales 121: 89-100.

Hoese, D.F., Larson, H.K. & Llewellyn, L.C. 1980. Family Eleotridae: gudgeons. pp. 169-185 19 figs in McDowall, R.M. (ed.) Freshwater Fishes of South-eastern Australia. Sydney : A.H. & A.W. Reed 208 pp., figs, 32 pls.

Johnson, J. 1993. Fishes of the Brisbane River. Fishes of Sahul, Journal of the Australian New Guinea Fishes Association 8(1): 347-352.

Krefft, G. 1864. Notes on Australian freshwater fishes, and descriptions of four new species. Proceedings of the Zoological Society of London 1864: 182-184.

Lake, J.S. 1978. Australian Freshwater Fishes. Melbourne : Thomas Nelson 160 pp. 140 figs.

Larson, H.K. & Hoese, D.F. 1996. Family Gobiidae, subfamilies Eleotridinae and Butinae. pp. 200-219 in McDowall, R.M. (ed.) Freshwater Fishes of South-eastern Australia. Sydney : Reed Books 247 pp.

Merrick, J.R. & Schmida, G.E. 1984. Australian Freshwater Fishes Biology and Management. Sydney : J.R. Merrick 409 pp. figs 280 col. figs.

Pusey, B.J., Kennard, M.J. & Arthington, A.H. 2004. Freshwater Fishes of North-eastern Australia. Collingwood, Victoria : CSIRO Publishing 684 pp.

Thomson, J.M. 1978. A Field Guide to the Common Sea & Estuary Fishes of Non-tropical Australia. Sydney : Collins 144 pp.

Unmack, P.J. 2001. Biogeography of Australian freshwater fishes. Journal of Biogeography 28: 1053-1089.