Western Rainbowfish, Melanotaenia australis (Castelnau 1875)

Other Names: Australian Rainbowfish, Dookoolkoodany, Gooljirimby, Northern Rainbowfish, Red-tailed Rainbowfish, Walmadi, Walmarri, Western Australian Jewel-fish, Western Australian Sun-fish, Western Rainbow Fish, Westralian Sunfish

Western Rainbowfish, Melanotaenia australis. Source: Michael Hammer. License: All rights reserved


A small highly-variable rainbowfish with 1-2 broad dark midlateral stripes, narrow yellow to reddish stripes along each scale row, and often 2-3 dark zigzag-like stripes along lower sides. Females are quite plain with slender bodies, while the males are deeper-bodied and strikingly coloured.

Courtship behaviour of Western Rainbowfish in the upper reaches of the Finniss River near Batchelor, Northern Territory.

Western Rainbowfish in the upper reaches of the Finniss River, Northern Territory.

Cite this page as:
Bray, D.J. & Gomon, M.F. 2022, Melanotaenia australis in Fishes of Australia, accessed 24 May 2024, https://fishesofaustralia.net.au/home/species/3047

Western Rainbowfish, Melanotaenia australis (Castelnau 1875)

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Common and widespread in river systems from the Pilbara region of Western Australia between the Ashburton River and the De Grey River, north-western Australia between the Fitzroy River, Western Australia, and the South Alligator River, Northern Territory, and south to Lake Woods, Northern Territory, Arnhem Land between the South Alligator River and the Walker River, and Groote Eylandt and Bickerton Island in the Gulf of Carpentaria, Northern Territory.

Inhabits freshwater rivers, creeks, swamps, marshy lagoons, lakes and reservoirs. Often forms aggregations at or near the surface, or along stream margins around vegetation or submerged woody debris.


Dorsal fin IV-VII + I, 7-12; Anal fin I, 16-21; Pectoral fin 12-16; Caudal fin 12 (branched rays).

Body oblong shaped, moderately elongate, laterally compressed; greatest body depth (adults > 50 mm SL): males 30.6-43.1, females 26.9-37.1 % SL; head length 24.3-29.0; snout length 7.2-8.6; eye relatively large, diameter 7.2-9.7; jaw teeth conical to caniniform, several rows extending outside of mouth; vomer with a solid band of well-developed teeth; teeth present on vomer and palatines.

Scales cycloid to slightly crenulate with well-developed radii; horizontal scale rows 10 to 13; vertical scale rows 33 to 35; predorsal scales 14 to 19; preopercle-suborbital scales 7 to 15.

Two separate dorsal fins; anal fin originates on anterior half of body; all soft segmented fin rays usually branched except first soft ray of anal and second dorsal fins; anal fin long-based; caudal fin emarginate to falcate.


To 12cm SL, commonly to 8cm.


Generally with 1-2 broad, dark mid-lateral stripes and series of narrow reddish stripes approximately along each scale row. Often also 2-3 dark zig-zag black stripes on the lower sides. There is much variation in colour pattern among different locations.


Omnivore - feeds on filamentous algae, aquatic and terrestrial insects, microcrustaceans, snails and other small invertebrates.


Reproduction may occur throughout the year with a peak in spawning activity from November to January. As with other rainbowfishes, females exhibit "trickle-spawning", scattering a small number of eggs daily amongst vegetation and root-masses.

Larvae are small at hatching, with little yolk, well-developed eyes, a well-developed feeding apparatus and gut, and commence feeding shortly after hatching.


A popular aquarium fish.


The species was at one time regarded as a subspecies of the Eastern Rainbowfish, Melanotaenia splendida. It hybridizes with M. splendida in the eastern edge of its range.
The Aboriginal names for this species in The Kimberley region of Western Australia include:
Bunuba language: Walmarri 
Gooniyandi language: Walmadi
Ngarinyin language: Gooljirimby
Nyikina language: Dookoolkoodany


The specific name is from the Latin australis (= southern). Castelnau considered that this species represented a new family and genus (Neoatherinidae: Neoatherina) that was endemic to Australia.

Species Citation

Neoatherina australis Castelnau, 1875,  Philadelphia Centennial Exhibition of 1876 :32. Type locality: Coast of Swan River Colony, Western Australia.


Bray, D.J. & Gomon, M.F. 2022


Atlas of Living Australia

Western Rainbowfish, Melanotaenia australis (Castelnau 1875)


Allen, G.R. 1982. Inland Fishes of Western Australia.  Perth : Western Australian Museum 86 pp. (as Melanotaenia splendida australis)

Allen, G.R. 1989. Freshwater Fishes of Australia. Neptune, New Jersey : T.F.H. Publications 240 pp., 63 pls. (as Melanotaenia splendida australis)

Allen, G.R. & Cross, N.J. 1982. Rainbowfishes of Australia and Papua-New Guinea. New Jersey : T.F.H. Publications 142 pp. figs. (as Melanotaenia splendida australis)

Allen, G.R., Midgley, S.H. & Allen, M. 2002. Field Guide to the Freshwater Fishes of Australia. Western Australian Museum, Perth. (as Melanotaenia australis and M. solata)

Brown, C. 2019. Melanotaenia australis. The IUCN Red List of Threatened Species 2019: e.T122905787A123382231. https://dx.doi.org/10.2305/IUCN.UK.2019-3.RLTS.T122905787A123382231.en. Accessed on 05 August 2022.

Castelnau, F.L. de 1875. Researches on the fishes of Australia. Intercolonial Exhibition Essays. 2. pp. 1–52 in, Philadelphia Centennial Exhibition of 1876 : Official Record. Melbourne. See ref online

Dally, G. 2010. Freshwater fishes of Lake Angurrkburna, Groote Eylandt, Northern Territory. MAGNT Research Report No. 13: 1-17.

Evans, J.P., Box, T.M., Brooshooft, P., Tatler, J.R. & Fitzpatrick, J.L. 2009. Females increase egg deposition in favor of large males in the rainbowfish, Melanotaenia australis. Behavioral Ecology 21(3): 465-469.

Hammer, M.P. 2018. Family Melanotaeniidae rainbowfishes. pp. 82-93 in Shelley, J.J., Morgan, D.L., Hammer, M.P., Le Feuvre, M.C., Moore, G.I., Gomon, M.F., Allen, M.G. & Saunders, T. (eds). A field guide to the freshwater fishes of the Kimberley. Murdoch, Western Australia : Murdoch University Print Production Team.

Kelley, J.L., Davies, P.M., Collin, S.P. & Grierson, P.F. 2017. Morphological plasticity in a native freshwater fish from semiarid Australia in response to variable water flows. Ecology and Evolution 7: 6595–6605. https://doi.org/10.1002/ece3.3167

Larson, H.K. & Martin, K.C. 1990. Freshwater Fishes of the Northern Territory. Northern Territory Museum of Arts and Sciences Handbook Series Number 1.  Darwin : Northern Territory Museum of Arts and Sciences 102 pp. 73 figs.

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

Leggett, R. & Merrick, J.R. 1987. Australian Native Fishes for Aquariums.  Artarmon : J.R. Merrick Publications 241 pp. 142 figs.

Lostrom, S., Evans, J.P., Grierson, P.F., Collin, S.P., Davies, P.M. & Kelley, J.L. 2015. Linking stream ecology with morphological variability in a native freshwater fish from semi-arid Australia. Ecology and Evolution 5(16): 3272–3287 https://doi.org/10.1002/ece3.1590

McGuigan, K., Zhu, D., Allen, G.R. & Moritz, C. 2000. Phylogenetic relationships and historical biogeography of melanotaeniid fishes in Australia and New Guinea. Marine and Freshwater Research 51: 713–723.

Morgan, D.L., Allen, M.G., Bedford, P. & Horstman, M. 2004. Fish fauna of the Fritzoy river in the Kimberley region of Western Australia - including the Bunuba, Gooniyandi, Ngarinyin, Nyikina and Walmajarri Aboriginal names. Records of the Western Australian Museum 22: 147-161.

Morgan, D.L., Allen, G.R., Pusey, B J. & Burrows, D.W. 2011. A review of the freshwater fishes of the Kimberley region of Western Australia. Zootaxa 2816: 1-64.

Phillips, R.D., Storey, A. & Johnson, M.  2009. Genetic structure of Melanotaenia australis at local and regional scales in the east Kimberley, Western Australia. Journal of  Fish Biology 74: 437-451. https://doi.org/10.1111/j.1095-8649.2008.02099.x

Taylor, W.R. 1964. Fishes of Arnhem Land. Records of the American-Australian Scientific Expedition to Arnhem Land 4: 44-307 figs 1-68. (described as Melanotaenia solata, type locality Groote Island, Northern Territory)

Young, M.J., Simmons, L.W. & Evans, J.P. 2009. Isolation and characterization of 12 novel DNA microsatellites in the Western Rainbowfish, Melanotaenia australis. Molecular Ecology Research 9: 1252-1254.

Young, M.J., Simmons, L.W. & Evans, J.P. 2010. Pre- and post-mating sexual selection favor large males in a rainbowfish. Behavioral Ecology and Sociobiology 64: 915–925.

Young, M.J., Simmons, L.W. & Evans, J.P. 2011. Predation is associated with variation in colour pattern, but not body shape or colour reflectance, in a rainbowfish (Melanotaenia australis). Journal of Animal Ecology 80: 183–191. https://doi.org/10.1111/j.1365-2656.2010.01759.x

Whitley, G.P. 1959. Fresh water fishes of Australia. Finchat 4(8): 11-13.

Zhu, D., Jamieson, B.G.M., Hugall, A. & Moritz, C. 1994. Sequence evolution and phylogenetic signal in control-region cytochrome b sequences of rainbowfishes (Melanotaeniidae). Molecular Biology and Evolution 11: 672-683.

Quick Facts

CAAB Code:37245012

Conservation:IUCN Least Concern

Fishing:Aquarium fish


Max weight:12 cm SL


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