This project will examine how Australian freshwater fish, frogs and invertebrates are affected by acute and chronic exposure to post-fire water quality changes such as elevated temperature, low oxygen levels and ash and sediment run-off. The research is needed in the aftermath of the 2019–20 wildfires as the threshold tolerances of freshwater aquatic animals for ash and sediment loads in Australian waterways are unknown. The results will inform waterway management and environmental flows, such as guiding: when to redirect run-off away from waterways; when to increase flows to dilute sediment slugs or to ensure that they move through sensitive habitats before they can adversely affect animal health; and when to undertake preventative population relocations to protect animals until waterways recover.