The temple staff alerted police who immediately removed the body to the SVRR Government Hospital here for post-mortem, police said.
There were no external injuries on the body, police said.
The devotee might have slipped into the water accidentally or committed suicide, they said.
The incidents comes three days after the 'float festivals' in the tank concluded, they said.
Protection grill enclosures arranged in the water around the tank to facilitate a safe holy dip for the devotees, was temporarily removed for the conduct of the five-day float festivals that concluded on March 23.
Pilgrims were not allowed to take the bath in the holy tank following the incident for about four hours, temple sources told PTI.
After some special rituals were conducted at the tank, the devotees were allowed to take holy dip in it, they added.