This is the shocking moment a Chinese river turned blood-red leaving thousands of fish dead.

According to environmental officials, the river in Huizhou in Guangdong China, changed colour after an accident led to dyeing paste being washed away in a discharge pipe from a local factory.

Huizhou residents reported that the water in the Chenjiang River turned red from noon through to evening on May 20, during which large numbers of fish died.

Staff from the Municipal Ecological Environment Bureau responded that the redness of the Chenjiang River water was due to the dyeing paste saying that it went from red to a muddy brown before eventually clearing as freshwater arrived from further upstream.

The official said that they had identified the source and attempted to isolate the contaminated water, and that further investigation was continuing.