We know from tests that the oxygen levels in the lake had dropped considerably, so the Environment Agency is recirculating water into the lake in an effort to stabilize oxygen levels.
Low oxygen levels could be due to a number of factors linked to environmental conditions such as decomposing algae or sediment stirred up by recent storms.
The surviving fish now have areas which are oxygenated and we will continue to work with the Environment Agency to make sure that oxygen levels stay at the required level.
Although tests for blue-green algae have returned negative, we would still like to remind people that there is no fishing on the lake until further notice to allow for the clean-up operation."
More top news
A frosty start in the east will clear to a pleasant winter's day for all - clear skies, sunny spells, staying dry but rather cold
A frosty start but once it clears, we will have a pleasant winter's day, clear skies, sunny spells and staying dry.
Cloud will keep much of Cornwall and South Devon frost free tonight but there's no denying that it will be cold tomorrow, if sunny.