What caused the foam on the River Thet?

The Environment Agency is investigating the source of the pollutant that caused extensive foam on the River Thet in October.

When will the River Thet be restocked with fish?

The Environment Agency will release 3,000 native fish into the River Thet on Monday as part of restoration efforts.

Why is the River Thet important?

The River Thet is a globally rare chalk stream, with a significant concentration of these unique waterways found in the East of England.

Home / Environment / River Foam Mystery: 3,000 Fish to Restock Thetford

River Foam Mystery: 3,000 Fish to Restock Thetford

3 Dec, 2025

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Summary

3,000 fish to be released into River Thet to aid recovery.
Pollution caused extensive foam and dead fish in October.
River Thet is a rare chalk stream vital for East Anglia.

River Foam Mystery: 3,000 Fish to Restock Thetford

The River Thet is set to receive a significant boost as 3,000 fish are reintroduced to combat the effects of a severe pollution incident. In October, an extensive section of the river in Thetford, Norfolk, was covered in a thick layer of foam, tragically resulting in the discovery of dead fish.

The Environment Agency is spearheading the restoration, planning to release a mix of native species, including roach, dace, and chub, into the water on Monday. This initiative is a critical step in helping the river, a rare chalk stream, regain its full ecological vitality. Specialist teams are continuing their investigation into the pollutant's source and conducting extensive water-quality tests.

This event follows a similar incident in December 2024, according to the local preservation group, Thetford River Group. The River Thet's status as a globally rare chalk stream, with nearly a third located in the East of England, underscores the importance of these recovery efforts. Continuous monitoring will assess fish survival rates and the river's overall recovery over the coming months.