Signs are being erected to warn dog owners to avoid letting their dogs near water in a Cheltenham park.
The Environment Agency have confirmed blue-green algae has been found in the water at Benhall Park.
It follows the news that a springer spaniel reportedly died after drinking algae from a brook at the park where warnings are now in place.
Cheltenham Borough Council say Pittville and Hatherley parks will also be tested as a precaution.