An investigation has been launched after 100 dead fish were found in a river.
Tests have been carried out be Natural Resources Wales on the water and laboratory results are expected soon.
The fish were found at Nant Cylla in Penpedairheol on Saturday, May 25.
In a statement, NRW said there were no clear signs of pollution but that officers are looking for any potential source upstream.
If any is found then action will be taken, the environmental body added.