Cause found for dead fish found in stream off River Usk near Brecon
At least 100 fish found dead in a stream off the River Usk in Powys died following the draining of a private fishing lake, say investigators.
The fish - small perch and roach - were discovered in a brook which flows into and out of the lake near Brecon.
Environment Agency Wales says the fish passed through the mesh covering an inlet pipe while the lake was being emptied for a safety inspection.
The agency said there was no evidence of environmental or ecological damage.
The fish and a large amount of silt were found in the stream about a mile from Brecon at around 13:30 GMT on Friday.
Environment Agency Wales said the owners had removed most of the fish from the lake before it was drained for a required 10-year inspection.
But investigators found that due to their small size, the perch and roach passed through the mesh covering an inlet pipe while the lake was being emptied, and died as a result.
The agency said its officers were planning to meet the owners of the lake to put in place measures to prevent such an incident happening again.