The management of Beijing's Chaoyang Park insisted that the water quality of a river that runs through it is safe, after the discovery of scores of dead fish.
In a statement on Sunday, the park said the fish likely died after being released by the public, rather than due to water pollution.
Fish put in the river by residents may fail to adapt to the environment, the park said, adding that the discovery of dead fish there is common.
Yet many members of the public are not convinced.
"The river is connected to rivers outside the park and it's hard to judge whether the water is polluted or not," a resident surnamed Wu told Beijing News.
Life aboard a fishing boat under bridge in city of Chongqing