Hundreds of fish that are meant to purify the water of the Tiesha River in Hangzhou, capital of Zhejiang province, turn up dead on plates every day.

Most of the fish, raised by Hangzhou's urban management department, are chubs, which consume large amounts of planktons and are capable of purifying river water.

The city's officials said it is "difficult to stop fishing" in the river as most fishermen come out "too early in the day or too late in the evening".