A nine-year-old boy, who went to fish in the Sarakki lake at Puttenahalli along with his four-year-old brother, drowned in the muddy waters on Monday afternoon.
Passersby who spotted the boys Vivek and Dhanush drowning, tried to rescue them, but Vivek had died by the time he was pulled out of the water.
Vivek was studying in third standard.
Dhanush, an LKG student, is undergoing treatment in the ICU at a private hospital.
Vivek and Dhanush, children of Renuka and Venkatesh, who runs Vivek Security Agency, regularly went for fishing in the lake, which is just about 200 metres from their house.
The lake had swollen due to the recent rains.
Dr Somayaji told Deccan Herald that the condition of Dhanush was still critical but stable.
The boy had consumed a lot of contaminated water and his blood had turned acidic. It may also lead to lung infection and other complications, Somayaji said.