The Service is responsible for the conservation and management of all native Tasmanian freshwater fish and many invertebrates. There are 25 species of native freshwater fish, 12 of which are endemic, being found only in Tasmania. Fifteen species are in the family Galaxiidae, two are eels (family Anguillidae) and the other six species are each in a different family.
The native species can be divided into three groups with regard to their habitat and breeding pattern.
River-dwelling freshwater species spend their entire life cycle in streams and rivers. They are the blackfish, pygmy perch and Swan galaxias. Blackfish are widespread across the north of Tasmania and have been introduced into other areas including the Huon River in the south-east and the Clyde River in central Tasmania. Pygmy perch occur in northern Tasmania including the Flinders and King Islands. The Swan galaxias has a very restricted distribution in the upper reaches of some streams in the eastern tiers.
Lake-dwelling freshwater species spend their entire life cycle in lakes and their tributaries. They include many of the Tasmanian endemic species with restricted distributions, such as the golden galaxias and paragalaxias species.
Migratory species move between the sea and freshwater streams at different stages of their life cycles. These include the species in whitebait runs and eels. These species are widespread around Tasmania in coastal streams. Some species (spotted and climbing galaxias) also occur in land-locked lake populations in the highlands.