Nannatherina balstoni Regan, 1906
Balston's pygmy perch

Family:  Percichthyidae (Temperate perches)
Max. size:  9 cm SL (male/unsexed); 9 cm TL (female); max. reported age: 3 years
Environment:  benthopelagic; freshwater; pH range: 6 - 6.5; dH range: 5 - 10
Distribution:  Oceania: coastal drainages of southwest Australia between Two People Bay (near Albany) and the Blackwood River. Also reported from the Goodga River to Gin Gin Brook, western Australia (Ref. 7300).
Diagnosis:   
Biology:  Is the rarest of all the endemic freshwater fishes of southwestern Australia. Inhabits coastal streams, lakes, ponds and swamps, where the water is dark and acidic (pH as low as 3.0) and has a large seasonal fluctuation in temperature (11-30°C) (Ref. 27892, 44894). Favors shallow water and is commonly found in association with tall sedge thickets (Ref. 44894). Larva feeds mainly on cladocerans, copepods and dipteran larvae, while juveniles and adults ingest mostly terrestrial fauna (Ref. 6398, 44894). Breeds in the middle of winter in response to flooding. Female lays between 500-1600 eggs each. The majority of adult perishes shortly after spawning at the end of their first year (Ref. 44894). Both male and female attain sexual maturity at the end of their first year of life when they have attained an average TL of 6.0 and 6.3 cm respectively (Ref. 27892). Co-occurs with Edelia vittata over part of its range, but is generally more scarce (Ref. 5259, 44894). Aquarium conditions: pH=7.2, H=8, 24°C water temperature, rock and plant cover, carnivore, peaceful community fish, egg layer (Ref. 6398).
IUCN Red List Status: Endangered (EN); Date assessed: 09 January 2019 (B2ab(i,ii,iii,iv)) Ref. (130435)
Threat to humans:  harmless


Source and more info: www.fishbase.org. For personal, classroom, and other internal use only. Not for publication.