'Farm silage' caused fish deaths at Madeley pool
Agricultural silage polluted a village pool in Staffordshire killing an estimated 100 to 200 fish, the Environment Agency (EA) has said.
The fish were found dead in Madeley, near Newcastle-under-Lyme, on Tuesday morning sparking a large rescue operation of surviving fish.
Tom Thornett, from the agency, said silage must have got in from a stream.
An investigation would look at whether anyone was "culpable" or there was reckless behaviour, he added.
Mr Thornett said it could also have been an accident.
Dozens of volunteers worked with firefighters and anglers to try to save hundreds of other fish in the pool, which were then taken to local fisheries.
Mr Thornett said: "Due to the sterling efforts of local anglers and the assistance of the fire brigade there were quite a lot of fish rescued and some oxygen has been pumped back into the pond to help build the levels up."
He said silage stripped oxygen from the water, causing fish to suffocate.
Further tests would be carried out at the pool, including checking oxygen levels, before the fish were returned.
Parish councillor Gary White said residents were "out in force" putting fish into buckets and paddling pools to try to save them.
Mr White said of the pool: "It's a major amenity for this village.
"There's a fishing club that operates from here, there's a Madeley pool society.
"We're in a conservation area so it's absolutely catastrophic for us."