Hundreds of dead fish found in River Weaver in Nantwich could be caused by low oxygen and high temperatures, says the Environment Agency.
And they say similar events are happening in rivers all over the North West.
People reported seeing lots of dead fish and many struggling to survive along various stretches of the river in and around Nantwich.
Today, an Environment Agency spokesperson said: “We continue to investigate a significant number of fish deaths and fish in distress incidents across Greater Manchester, Merseyside and Cheshire.
“We believe that many of the problems we are seeing are as a result of low dissolved oxygen due to a combination of the high temperatures we have experienced recently, and the low atmospheric pressure caused by the thunderstorms.
“However, our officers are investigating at multiple locations to rule out any other causes such as pollution.
“It is important that members of the public who spot fish in distress report it to our 24/7 incident hotline 0800 80 70 60 so that our officers can investigate.”
It could be related to the sewage being discharged from the White Lion Public House in Hankelow. It’s affected the fish in Hankelow Pond and the Lilly Pads have not appeared this year,