The Murray hardyhead is one of the most threatened freshwater fish in Australia, surviving in a handful of mostly isolated wetlands of the Murray–Darling Basin. This paper summarises the biology of Murray hardyhead, and discusses the various management actions undertaken to prevent its extinction during the recent Millennium drought. Lessons learnt from these conservation efforts can guide future conservation of aquatic biota in modified drought-prone freshwater systems.

When severe drought struck the lowermost reaches of the Murray–Darling Basin, Australia, several already threatened freshwater fishes faced imminent extinction. A team of researchers, managers and community members joined forces in urgent efforts to save the fish, which included rescues, captive breeding, habitat works and environmental watering. The outcomes and lessons learned from this urgent activity will help guide local and international efforts to conserve freshwater biodiversity.

A 32-year monitoring program has delivered a variable assessment of the success or failure of a translocation of 66 adults of the endangered Macquarie perch in south-eastern Australia. Following 5 years of non-detection, a self-sustaining population had established within 10 years, but then were again undetectable after ~25 years. Prolonged drought is thought the most likely reason for the ultimate decline, highlighting the importance of variable climate on future conservation efforts and the need for long-term monitoring.

This paper discusses the conservation effort that has been directed towards red-finned blue-eye, a fish that has recently been included in a book published by the IUCN highlighting the plight of the 100 most endangered species worldwide. The work aimed to investigate whether control of gambusia was possible and whether relocation of the endangered species was a suitable population recovery technique. Both methods have been successful, and combined with other techniques it may be possible to prevent this species becoming extinct.

The Pedder galaxias was saved from the brink of extinction after a long and intensive program lasting in excess of thirty years. During this time many different strategies were implemented to save the fish, with translocation proving to be the most effective and beneficial. Many lessons have been learnt that can inform conservation programs for other critically endangered freshwater fish facing similar challenges and threats.

Pygmy perches are much smaller relatives of Australia’s largest freshwater fish, the iconic Murray cod, but unlike their larger cousin, their presence, let alone conservation needs, is little known by the general public. This review highlights that conservation management for pygmy perches, along with many other small species that make up the majority of the Australian and global fish fauna, reflects this low level of awareness. Observations and recommendations are made for an integrated approach to the future conservation of the two pygmy perches that may also be applied elsewhere in the world.

Alterations to water level regimes threaten freshwater fishes; however, suitable operation of impoundments could help manage fish populations. Water levels were purposely manipulated in a lake system during two years and this assisted spawning and recruitment of a threatened fish species (Galaxias auratus) following a prolonged drought. Given adequate ecological knowledge, hydrological manipulations can assist recovery of threatened fishes in impoundments.

Fragmentation is a major threat to freshwater fish, especially those that require movement among habitats to fulfil life history requirements. A specifically designed fishway has increased the length of stream accessible for spawning for a population of the endangered Macquarie perch in the Cotter River, Australia. The success of the fishway has proven timely because enlargement of a downstream reservoir will inundate and destroy the majority of spawning sites of this species downstream of the fishway.