Scientists derided a major campaign in Guangxi province to catch piranhas after two residents were reportedly bitten by fish in the Liu River last week.
Officials in the city of Liuzhou on Monday mobilised more than a dozen fishing boats and offered residents 1,000 yuan (HK$1,230) for each piranha caught.
Fishermen cast nets more than 10 kilometres long that plumb the depths of the riverbeds, and used large quantities of meat, blood and organs as bait. More than 10kg of nearly every species of fish in the Liu River was caught, but not a single piranha, the Liuzhou Daily reported.
Piranhas are thought to have been dumped in rivers by people who bought them as pets but tired of them.
Some scientists say the campaign is foolish and destructive.
'I'm afraid the government is doing greater harm to the ecosystem than the piranhas,' said Luo Jianren , a researcher with the Pearl River Fisheries Research Institute in Guangzhou.
Luo said the number of piranhas was unlikely to increase significantly in Chinese rivers because their waters are colder and less acidic than the River Amazon, where the fish, with their razor-sheep teeth and reputation for ferocity, originate.