Western Rainbowfish, Melanotaenia australis (Castelnau 1875)

Other Names: Australian Rainbowfish, Northern Rainbowfish, Red-tailed Rainbowfish, 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.

Genetic studies have shown that Melanotaenia solatus is a junior synonym of M. australis.

Cite this page as:
Bray, D.J. & Gomon, M.F. 2020, Melanotaenia australis in Fishes of Australia, accessed 16 May 2022, https://fishesofaustralia.net.au/home/species/3047

Western Rainbowfish, Melanotaenia australis (Castelnau 1875)

More Info


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 a range of environnments including 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.


Omnivores - feed on filamentous algae, aquatic and terrestrial insects, microcrustaceans, snails and other small invertebrates.

Western Rainbowfish are preyed upon by a range of other fish species, including archerfish, Barred Grunter, Flathead Goby, Salmontail, Sooty Grunter and Spangled Perch.


Reproduction may occur throughout the year with a peak of 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.


Other scientific names used for this species:Melanotaenia solata, Melanotaenia splendida australis, Neoatherina australisNematocentris australis.

Species Citation

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


Bray, D.J. & Gomon, M.F. 2020


Australian  Faunal Directory

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.

Allen, G.R. & Cross, N.J. 1982. Rainbowfishes of Australia and Papua New Guinea. Sydney (Australia): Angus and Robertson.

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)

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.

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

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

Ivantsoff W, Crowley L, Howe E, Semple G. 1988. Biology and early development of eight fish species from the Alligator Rivers region. Technical memorandum 22, supervising Scientist for the Alligator Rivers Region. Canberra (Australia): AGPS.

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 Open access

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 DOI: 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.

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. (as Melanotaenia solata)

Young, M.J., Simmons, L.W. & Evans, J.P. 2009. Isolation and characterization of 12 novel DNA microsatellites in the Western Rainbowfish, Melanotaenia australis. Mol. Ecol. Res. 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. DOI: 10.1111/j.1365-2656.2010.01759.x Open access

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

Fishing:Aquarium fish


Max weight:12 cm SL


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