There was a stir Wednesday in Bidhan Nagar area of Siliguri town in West Bengal when a large number of fish was found dead and floating on the Motia river, an official said.
Panic-stricken residents moved their cattle away from the area, fearing they may die after drinking water from the river in Darjeeling district.
They also kept vigil so that no one took the fish to the market for selling.
A team from the state fisheries department went to the spot and collected samples of the river water and the dead fish.
"The samples are being sent for forensic examination," said deputy director of the department's North Bengal zone Uttam kumar Panja.
