Thousands of fish were found dead in Kottanatham Lake, near Kondalampatti, here on Wednesday, leading to allegations of discharge of industrial effluents. Dead fish were found floating in the 350-acre lake that helps irrigate farms in Chinneri, Poolampatty, Keeranur and Periyur. Villagers said they used the water to irrigate 400 acres and many were also involved in fishing in the lake to earn a livelihood. However, industrial effluents from companies located in the area were let into the lake, causing pollution, they alleged. The villagers said though many petitions were submitted, no action was taken to check the effluent discharge. The fish had died over the last two days and foul smell emanated from the lake. The villagers wanted the dead fish to be removed immediately.