Yarra Pygmy Perch, Nannoperca obscura (Klunzinger 1872)

Yarra Pygmy Perch, Nannoperca obscura. Source: Tarmo Raadik. License: All rights reserved


A small dusky, pale brownish-grey or olive-green pygmy perch becoming pale below, with darker chevron-shaped markings on the rear of the body, transparent to pale yellowish to blackish fins, and a pupil that is somewhat oblong. The Yarra Pygmy Perch differs from other Nannoperca species in having the pre-orbital bone not completely covered by skin, exposing its serrated lower edge. 

The species was described from the 'Yarra Lagoon, near Melbourne'. Unfortunately, Yarra Pygmy Perch are now extinct in the Yarra River.

Cite this page as:
Bray, D.J. & Thompson, V.J. 2022, Nannoperca obscura in Fishes of Australia, accessed 15 Apr 2024, https://fishesofaustralia.net.au/home/species/4459

Yarra Pygmy Perch, Nannoperca obscura (Klunzinger 1872)

More Info


Endemic to temperate waters of the Bunyip River system, Victoria, westwards to the Finniss River, Bool Lagoon and Lake Alexandrina in eastern South Australia.

Populations that once inhabited the Yarra River and Dandenong Creek near Melbourne, are now presumed extinct. Remaining populations have become fragmented due to water regulation and habitat loss.

Typically inhabits slow-flowing to still waters with abundant submerged and emergent aquatic vegetation, and often woody debris - such as lakes, ponds, , along with pools in slow to moderately high-flowing rivers and streams. 


Dorsal fin  VIII-IX, 7-9 (usually IX, 9); Anal fin III, 6-7; Pectoral fin 11-13 (usually 12).

Body oblong, compressed; dorsal profile more strongly arched than ventral profile; head large, dorsal profile straight; snout pointed; eye of moderate size, dorsolateral; mouth small, terminal, slightly oblique, protractile; jaw reaches back to front of eye; jaws, vomer and palatines with narrow bands of villiform teeth; lower, free edge of preorbital bone straight, strongly serrated; numerous distinct pores on head and operculum.

Scales moderately-large, finely ctenoid without circular ridges; scales present on head, opercula and cheeks; lateral line of interrupted series of tubed scales; mid-lateral scales 28-30; transverse scale rows 12-13.

A single dorsal fin with an anterior spiny section and posterior soft section separated by deep notch; anal fin opposite and similar to soft part of dorsal fin; pectoral fins small, rounded, positioned low on sides; ventral fins small, pointed, set well forward on abdomen; caudal fin moderately large, truncate or rounded.


To 7.5 cm SL, commonly to 5cm.


Olive green above, greenish-brown laterally, yellowish-white below, with darker scale margins and a faint reticulate pattern. Opercular region with golden sheen. Several dark blotches mid-laterally. Fins clear, fawn to orange, often with dark margins; pelvic and anal fins often with dark anterior edge. Caudal peduncle with a dark spot.
Prior to spawning, the pelvic fins of the male become black, the leading edge of the anal fin darkens and the dorsal and anal fins become an intense brownish-orange.


Feeds mostly on insects, insect larvae and planktonic crustaceans. The species may also consume small molluscs.


Little is known of the biology of this species. Spawning occurs in September to October at water temperatures between 16 and 24°C. Like other pygmy perches, this species presumably spawns large demersal eggs amongst aquatic vegetation.

The species is short-lived, with individuals living less than 5 years.


IUCN Red List: Endangered

EPBC Act 1999: Vulnerable

Victorian Flora and Fauna Guarantee Act 1988: Threatened

Populations of Yarra Pygmy Perch have declined in recent decades, due to habitat loss and predation by, and competition with introduced species such as Redfin (Perca fluviatilis) and Brown Trout (Salmo trutta).

Major threats include habitat degradation and loss, altered flow regimes; predation by Redfin Perch, Perca fluviatilis, Brown Trout, Salmo trutta and Rainbow Trout, Oncorhynchus mykiss; habitat destruction by Common Carp, and competition and predation by Eastern Gambusia, Gambusia holbrooki; affects of climate change


Yarra Pygmy Perch form small shoals, often mixing with Southern Pygmy Perch, Nannoperca australis.

Similar Species

The Yarra Pygmy Perch differs from the Southern Pygmy Perch, Nannoperca australis, in having a smaller mouth, a serrated preorbital bone, and in having a slightly notched pupil rather than one which is round. Fins of breeding males turn black compared with the bright red fins of N. australis.


The specific name obscura is from Latin (= darkened) in reference to the dark fins of breeding males.

Species Citation

Paradules obscurus Klunzinger, 1872, Arch. Naturg. 38(1): 20. Type locality: Yarra lagoon, Melbourne, Victoria.


Bray, D.J. & Thompson, V.J. 2022


Atlas of Living Australia

Australian Faunal Directory

Catalog of Fishes

Yarra Pygmy Perch, Nannoperca obscura (Klunzinger 1872)


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Buckley, S.J., Brauer, C.J., Unmack, P.J., Hammer, M.P. & Beheregaray, L.B. 2-22. Variation in intraspecific demography drives localised concordance but species-wide discordance in response to past climatic change. BMC Ecology and Evolution 22: 35. https://doi.org/10.1186/s12862-022-01990-2

Buckley, S.J., Domingos, F.M.C.B., Attard, C.R.M., Brauer, C.J., Sandoval-Castillo, J., Lodge, R., Unmack, P.J. & Beheregaray, L.B. 2018. Phylogenomic history of enigmatic pygmy perches: implications for biogeography, taxonomy and conservation. Royal Society Open Science http://doi.org/10.1098/rsos.172125

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Carvalho, D., Rodriguez-Zarate, C., Hammer, M. & Beheregaray, L. 2011. Development of 21 microsatellite markers for the threatened Yarra pygmy perch (Nannoperca obscura) through 454 shot-gun pyrosequencing. Conservation Genetic Resources 3: 601–604. doi: 10.1007/s12686-011-9413-8

Castelnau, F.L. de 1872. Contribution to the ichthyology of Australia. 1. The Melbourne fish market. Proceedings of the Zoological and Acclimatisation Society of Victoria 1: 29-242 1 pl. (described as Microperca yarrae)

Crook, D., Macdonald, J., Belcher, C., O’Mahony, D., Dawson, D., Lovett, D., Walker, A. & Bannam, L. 2008. Lake Condah Restoration Project – Biodiversity Assessment. Arthur Rylah Institute for Environmental Research Technical Report Series No. 180, Department of Sustainability and Environment, Heidelberg, Victoria.  

Donnelly, A.J. & Grieves CJ. 1992. Yarra Pigmy Perch (Edelia obscura) in the Fitzroy River, South Western Victoria. Victorian Naturalist 109(2): 54-55.  

Hammer M.P., Bice C.M., Hall A., Frears A., Watt A., Whiterod N.S., Beheregaray L.B., Harris J O., Zampatti B. 2013. Freshwater fish conservation in the face of critical water shortages in the southern Murray–Darling Basin, Australia. Marine and Freshwater Research 64: 807-821.

Hammer, M.P., Unmack, P.J., Adams, M., Johnson, J.B. & Walker, K.F. 2010. Phylogeographic structure in the threatened Yarra pygmy perch Nannoperca obscura (Teleostei: Percichthyidae) has major implications for declining populations. Conservation Genetics 11: 213–223 

Hammer, M.P. & Walker, K.F. 2004. A catalogue of South Australian freshwater fishes, including new records, range extensions and translocations. Transactions of the Royal Society of South Australia 128(2): 85-97

Jones, M., Tinkler, P., Lindeman, M., Hackett, G., & Pickworth, A. 2008. Threats, distribution and abundance of Yarra Pygmy Perch in Victoria during a drought period. Arthur Rylah Institute for Environmental Research Technical Report Series No. 184, Department of Sustainability and Environment, Heidelberg, Victoria.  

Klunzinger, C.B. 1872. Zur Fische-fauna von Süd Australien. Archiv für Naturgeschichte 38(1): 17-47 pl. 2 (p. 20, as Paradules obscurus) See ref at BHL

Koehn, J.D. & Morison, A.K. 1990. A review of the conservation status of native freshwater fish in Victoria. Victorian Naturalist 107(1): 13-25.  

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Kuiter, R.H. & Allen, G.R. 1986. A synopsis of the Australian pygmy perches (Percichthyidae), with the description of a new species. Revue Française d'Aquariologie et Herpétologie 12(4): 109-116 

Kuiter, R.H., Humphries, P.A. & Arthington, A.H. 1996. Family Nannopercidae. pp. 168-175 in McDowall, R.M. (ed.) Freshwater Fishes of South-eastern Australia. Sydney : Reed Books 247 pp.

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

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Saddlier, S. & Hammer, M. 2010. National Recovery Plan for the Yarra Pygmy Perch (Nannoperca obscura). East Melbourne, Victoria: Department of Sustainability and Environment. Available from: http://www.environment.gov.au/biodiversity/threatened/publications/recovery/yarra-pygmy-perch.html.  

Saddlier, S., Koehn, J. & Hammer, M. 2013. Let's not forget the small fishes – conservation of two threatened species of pygmy perch in south-eastern Australia. Marine and Freshwater Research 64: 874–886. doi: 10.1071/mf12260  

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Unmack, P.J., Hammer, M.P., Adams, M. & Dowling, T.E. 2011. A phylogenetic analysis of pygmy perches (Teleostei: Percichthyidae) with an assessment of the major historical influences on aquatic biogeography in southern Australia. Systematic Biology 60(6): 797–812 https://doi.org/10.1093/sysbio/syr042

Wedderburn, S.D., Whiterod, N.S., Barnes, T.C. & Shiel, R.J. 2020. Ecological aspects related to reintroductions to avert the extirpation of a freshwater fish from a large floodplain river. Aquatic Ecology 54: 281–294 https://doi.org/10.1007/s10452-019-09742-z

Wedderburn S., Whiterod N.S. & Gwinn, D.C. 2019. Determining the Status of Yarra Pygmy Perch (Nannoperca obsura) in the Murray–Darling Basin. Report to the Murray-Darling Basin Authority and the Commonwealth Environmental Water Office. The University of Adelaide and Aquasave–Nature Glenelg Trust, Adelaide, 32 pp.

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Quick Facts

CAAB Code:37311219

Conservation:IUCN Endangered


Max Size:7.5 cm SL


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