A councillor is calling for more action to clean up a polluted waterway.
In 2017, about 500 fish were killed due to pollution in the Laugherne Brook in Worcester and since then the Environment Agency (EA) has had to work to increase the water's oxygen levels.
Councillor Richard Udall said there had been over 50 pollution incidents in the brook over the past five years.
The EA said it takes its "responsibility to protect the environment very seriously".
Mr Udall, from Worcestershire County Council, said people were "still upset" about the 2017 incident.
'Killing our wildlife'
"I do believe it is now time for the Environment Agency to come up here and make sure the brook is clear and free from pollution," he said.
"I am concerned that incidents are continuing, it is just killing our natural wildlife."
He said fish should be restocked to improve the area's biodiversity.
"The area used to have kingfishers, they haven't been seen since the fish have left, it used to have an otter, that hasn't been seen recently either," Mr Udall said.
"All in all, the biodiversity of the area is really dependent on the fish being in the brook."
But the EA said its investigation into the pollution incident at Laugherne Brook was ongoing and a decision to restock it could only be considered once this was complete.
"The water quality and the ecological health of rivers must improve," a spokesperson for the EA said.
"The main sources of pollution are agriculture and the water industry and there is a growing threat from plastics and forever chemicals."
The agency said monitoring the water quality was "essential" and that it had spent millions on collecting data from rivers since 2016.