Officials at the Environment Agency have blamed the recent heatwave for the deaths of thousands of freshwater fish, across the region.
The intense heat has caused oxygen levels in the water to plunge. There have been reports of fish in distress in Welney in Norfolk and Tiptree in Essex.
The Environment Agency is able to treat affected waterways with River Rover aeration equipment if they are e notified.
More top news
Icy stretches will form tonight as temperatures drop and wintry showers develop later.
A woman has been banned from keeping all animals for three years after admitting neglecting her cat and four kittens - two of whom died.
With the cold weather expected to last for at least the next five days, the Met Office has issued various snow and ice warnings.