Pedder Galaxias, Galaxias pedderensis Frankenberg 1968

Originally endemic to Lake Pedder and Lake Maria, and their tributaries and surrounding swamps, Tasmania. This species became extinct in its native habitat following the flooding of Lake Pedder in 1972 for hydroelectric power generation. However, two translocated populations exist in Lake Oberon in the Western Arthur Range south-west of Lake Pedder, and the Strathgordon water supply. 

Adults inhabit the darkly tannin-stained water with rocks and boulders around lake margins and around vegetation or woody debris in streams entering lakes. Juveniles shoal in open water near lake margins. The last fish found in their natural habitat lived in the lower meandering sections of two tributary streams, preferring areas where the streams are heavily shaded, sandy-bottomed and highly convoluted with deep pools and instream cover.

Dorsal fin 10-13; Anal fin 12-16; Pectoral fin 11-14; Vertebrae 51-54; Gill rakers, first arch 10-17.

Body very slender, elongate, depth at anus 6.7-11.5 in SL. Head long, strongly depressed, eyes dorsolateral, level with top of head. Jaws about equal in length.

Scales absent.

Fins small. Dorsal-fin origin well behind pelvic fins but originating forward of the vent and anal fin. Anal fin origin behind dorsal-fin origin. Caudal fin truncate to slightly emarginate.

To 16 cm SL, commonly 7-8 cm. Adults usually range in length from 7.5-12 cm, but may grow up to 16 cm; size at maturity is ~9.5 cm fork length in females and ~7.5 cm fork length in males.

Greenish brown, the back and sides covered with distinct but very irregular dark blotches extending to the fleshy bases of the dorsal, tail and anal fins. The belly is off-white. Gold iridescence is often evident.

Feeds mainly on aquatic insect larvae, aquatic beetles, small crayfish and copepods.

The sexes are separate and the lifecycle is completed in freshwater. Spawning occurs once a year in Spring at 3-4 years of age in small streams. Females deposit about 150-1200 small adhesive eggs about 2.5 mm in diameter in sheltered positions amongst vegetation, rocks or woody debris.

The larvae hatch after 3-4 weeks. It is likely that the original lake served as a nursery area for the larvae and juveniles, which live in open water

Fish live for 5 to 6 years.

Pedder Galaxias are totally protected and may not be taken without a permit.

IUCN Red List of Threatened species: Critically Endangered 

EPBC Act 1999: Extinct in the Wild 

Tasmanian Threatened Species Protection Act 1995: Endangered

Habitat detruction, along with predation and competition from introduced species have eliminated the Pedder Galaxias from its original habitat. The colonisation of the flooded Lake Pedder by non-native Brown Trout and native Climbing Galaxias is thought to have resulted in the decline of Pedder Galaxias during the 1980’s. In 1996, the last Pedder Galaxias was seen in its remaining natural habitat. 

A translocated population is now the only known breeding population of the Pedder Galaxias. Between 1991 and 1992, 31 fish were moved into Lake Oberon, a remote fish-free lake in south-west Tasmania in an attempt to save the species. The Pedder Galaxias are thriving in this new habitat and in 2001 some were moved to a second artificial habitat.

Prior to the inundation of Lake Pedder, juveniles could be seen swimming around the lake shores in large schools. Adults inhabited the lake and surrounding swamps and streams. They preferred rock and boulder habitat and were found amongst cover in streams entering the lake. The last collected individuals lived in these tributary streams

The 1972 flooding of Lake Pedder inundated another headwater catchment, allowing introduced and other native fish species to enter Lake Pedder. As the colonising fish proliferated, numbers of the Pedder Galaxias declined markedly (Chilcott et al. 2013). 

Galaxias pedderensis Frankenberg 1968, Australian Zoologist 14(3): 268-274. Type locality: Lake Pedder, Tasmania.

Gomon, M.F. & Bray, D.J. 2025

Atlas of Living Australia