Galaxias fontanus, the Swan galaxias, is a species of fish in the family Galaxiidae. It is endemic to eastern Tasmania, Australia. The brownish-olive fish is only found in the Trout-free headwaters of the Swan and Macquarie River catchments. Natural populations are very small and fragmented, however the species has been successfully introduced into other predator-free streams. It is listed as Endangered on the IUCN Red List and Environment Protection and Biodiversity Conservation Act 1999.