There are warnings for people to avoid swimming in lakes, rivers and other open water.
It follows the death of 17-year-old Russell O'Neill who lost his life over the weekend, swimming in a quarry near the Malvern Hills in Worcestershire.
Charlotte Grant reports.
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The Range Rover had a number of parking tickets.
The 74-year-old was on vacation in Blackpool but is from the Midlands.
Oxygen levels are believed to have suddenly dropped, causing the fish to die.