Mysterious Foam Kills Fish in Thetford River

On Saturday, October 14th, 2025, authorities in Thetford, Norfolk reported the appearance of thick white foam on the River Thet, a local waterway. The Environment Agency, which is responsible for environmental protection in the area, has since confirmed that small dead fish and fry were found in the river.

A spokesperson for the Environment Agency stated that the incident is "obviously upsetting" and that the agency is investigating the source of the pollutant, which they describe as an "unknown substance." The agency has been on-site to collect samples from the river, and they expect the foaming to naturally reduce as the increased rainfall over the next few days dilutes the pollutant.

Firefighters also attended the scene and warned the public not to enter the water or allow their pets to swim in or drink from the river. An Anglian Water spokesperson has stated that the foam was caused by a "third-party" and was not from any of their equipment or assets in the area.

Local angler Brian Holt, 65, described the scene, saying "It looked like someone had put loads of Fairy Liquid in the water because it was white foam and was just getting worse." Holt, who fishes in the area every other weekend, reported seeing "fish floating" in the water.

The Environment Agency has stated that they will survey the longer-term impacts once the pollutant has dissipated. They also noted that they had responded to a similar incident involving foam on the River Thet on December 23rd, 2024, but were unable to identify the source at that time.