BRITISH Waterways has warned people that possible poisonous blue-green algae has been found at Olton Reservoir.
The algae, which has also been detected in the Grand Union Canal between Olton and Hatton, can harm fish and other wildlife.
There are many species of the flora, not all of them toxic, but the authorities are warning people to be on the safe side.
“The canal is still very much open and we’re issuing this advice purely as a precaution as most people wouldn’t come into contact with the water,” said a spokesperson.
Direct contact with the algae can cause an allergic reaction - including itchy eyes, a rash and hay-fever like symptoms.
The algae is expected to disperse naturally as the weather gets colder.