The Paroo occupies a unique niche within the Murray-Darling Basin. Located in the arid north-west, it behaves and presents in a similar way to thousands of years ago, with unpredictable floods and flows driving booms and busts of predominantly native fauna and flora. The Paroo has consistently ranked amongst the healthiest catchments in the Murray-Darling Basin in ecological audits, with lack of large-scale river regulation and isolation underpinning its individuality. Repeated monitoring of the aquatic fauna of the Paroo since 2019 represents the most comprehensive and complete study of the wildlife of this comparatively unknown catchment, and has included many previously unsurveyed areas, as well as ephemeral lakes and waterholes. Following a succession of wet seasons, the aquatic fauna of the Paroo appears to be in remarkably good condition, with population booms of most native fish and notably small populations of introduced species. The Paroo has the potential to provide useful insights that may be applicable when remediating more regulated catchments. The results suggest that if the effects of river regulation can be minimised, native populations of fish and other aquatic fauna may be able to compete effectively with alien species and maintain healthy populations if patterns of flows and flooding can be provided, restored or imitated.