'Poison' probe as 26,000 fish die on Rhondda trout farm
South Wales Police are investigating a suspected poisoning incident that has killed thousands of fish at Blaenrhondda.
Upper Rhondda Angling Association says it believes the action at the trout farm was malicious.
The fishing club estimates it has lost 26,000 fish from fry to 1lb (0.5kg) trout.
Club members say the incident has wiped out two years worth of stock and threatens the association's future.
One, Robert Langley, said it was "gut wrenching" to see so many dead fish.
"The club could die out. This was the future stock for two years, maybe more," he said.
Fish from the trout farm are used to stock the club's private fishing at Llyn Fawr.
The Environment Agency said it was also carrying out an investigation, but confirmed that the Rhondda Fawr river has not been affected by the incident.
"We have taken water samples at the fish farm and we await the results," said a spokesperson.
"In the meantime we will continue to offer this private fish farm any help we can provide."
It is understood the dead fish will be removed during the weekend and are likely to be incinerated.
South Wales Police are also appealing for information.