Millions of fish have died in the Darling River in western New South Wales due to a shortage of oxygen caused by a recent heatwave. The police and volunteers from the conservation organization OzFish are cleaning up fish carcasses, but not all of them can be collected. OzFish volunteers are also conducting a search and rescue operation to save any remaining native fish in the river. The cause of the fish deaths is hypoxic blackwater, likely caused by drought and human activity in the Murray-Darling Basin.

The Australian federal and state governments are working together to address the issue. The dead fish, which include native species like bony bream and golden perch, will be removed using a netting process by skilled contractors. NSW Police Commander Brett Greentree assured locals that the water supply remains of the highest quality. However, a nitrogen influx and algal blooms are expected due to the fish carcasses sinking to the riverbank, which could lead to further problems in the future. Cassie Price, head of programs for OzFish, warns about the additional problems that could arise as a result.