Swan Galaxias

Galaxias fontanus
Swan Galaxias - Marinewise © 2025 MarineWise

Quick Facts

Scientific name Galaxias fontanus
Other names Tasmanian Mudfish, Swamp Galaxias
Size Up to 13.5 cm (5.31 in)
Weight Under 20 grams

Distribution

Habitat & AU Distribution Freshwater rock pools of streams & creeks often near wood debris
Depth Range 0 - 3 m (10 ft)
Swan Galaxias Distribution

Interesting Info

  • The Swan Galaxias is a freshwater fish species endemic to eastern Tasmania. Today it survives only in a few tiny headwater streams of the Swan and Little Swan River catchments in eastern Tasmania.
  • Its body is slender and semi-transparent, with a pale golden-brown colour and scattered dark flecks along its sides, helping it blend with leaf litter and pebbly stream bottoms.
  • The Swan Galaxias prefers clear, cool, shallow streams with gravelly beds and plenty of cover from vegetation and woody debris.
  • They are very poor swimmers, which makes them vulnerable to being pushed out of their habitat by stronger, introduced fish like trout.
  • They feed mostly on small aquatic insects and larvae, especially midges, mayflies, and caddisflies.
  • Once widespread in the Swan River catchment, they now survive only in fragmented, isolated populations, many cut off from one another by barriers.
  • Breeding takes place in autumn (April–May), when females deposit adhesive eggs among submerged vegetation, roots, or leaf litter in shallow, flowing water.
  • Newly hatched larvae are tiny and drift downstream into still pools, where they feed and grow before moving back into faster-flowing headwaters as juveniles.
  • Their biggest threats are predation and competition from introduced trout, as well as habitat loss and reduced stream flows.
  • The lifespan is short, usually 2–3 years, with most fish breeding only once before they die.
Species Interaction

Conservation

The Swan Galaxias is listed as Endangered under the EPBC Act and by the IUCN Red List. Its survival is threatened by introduced trout, habitat fragmentation, and reduced stream flows. Ongoing conservation programs are essential to protect this rare Tasmanian species.

Scientific Classification

Kingdom: Animalia

Phylum: Chordata

Class: Actinopterygii

Order: Salmoniformes

Family: Galaxiidae

Genus: Galaxias

Species: Galaxias fontanus

Conservation Status

Swamp galaxias is considered to be a threatened species in Tasmania, Australia, where it is found. It is listed as “Endangered” under the Tasmanian Threatened Species Protection Act 1995 and the Commonwealth Environment Protection and Biodiversity Conservation Act 1999.