Mass fish deaths in Australia's second longest river have been blamed on low oxygen levels.
Footage showed a slick of hundreds of thousands of silvery bodies blanketing the surface of the Darling River near the town of Menindee in a remote part of New South Wales, around 620 miles (1,000km) west of Sydney.
Authorities said the die-off was down to "dissolved oxygen levels" and state fisheries officers have been sent to assess the situation, with the rotting carcasses causing a putrid stench for residents.
It follows previous large-scale fish deaths in the same area in 2018 and 2019 as a result of poor water quality and sudden temperature changes.
The state planning and environment agency warned river oxygen levels could fall further this weekend as temperatures rise, before cooler conditions return next week.
The NSW Department of Planning and Environment's water division posted on Twitter: "Dissolved oxygen levels remain a concern for fish health.
"There is a large number of fish deaths (predominantly bony herring) in the Darling River between Lake Wetherell and Menindee township."
The NSW Department of Primary Industries (DPI) said it would continue to monitor the risks to fish health in the area.
It said: "The amount of dissolved oxygen water can hold decreases with increasing water temperature, which can add additional stress to fish that may already be struggling."