Dead fish found after thick foam fills River Thet

Dead fish have been found on a river where thick white foam appeared, the Environment Agency has said.

The substance was seen on the waterway along the River Thet in the centre of Thetford, Norfolk, on Saturday.

A spokesperson for the Environment Agency said: “Our officers have seen small dead fish and fry. This is obviously upsetting.”

They said it was investigating the incident, adding that “the pollutant is an unknown substance”.

The Environment Agency said it had been on site to take samples from the river.

A spokesperson said: “We have detected the source and expect the foaming to reduce naturally as it is diluted by the rain that will increase the flow of the river over the next few days.”

Firefighters also attended and Norfolk Fire Service warned people not to enter the water or allow their pets to swim in or drink from the river.

An Anglian Water spokeswoman said checks confirmed the foam had been caused “by a third-party” and was not from any of “our equipment or assets in the area”.

Brian Holt, 65, a local angler, said: “It looked like someone had put loads of Fairy Liquid in the water because it was white foam and was just getting worse.”

Mr Holt said he saw “foam everywhere coming down the river” when fishing.

He said he usually fished in the area every other weekend and saw “fish floating” in the water.

A spokesperson for the Environment Agency said: “We will survey the impacts once the pollutant has gone to assess longer-term impacts.”

They added that its officers had attended an incident involving foam on the River Thet on 23 December 2024 but were unable to identify the source on that occasion.