The Haridra Nadhi is the sacred tank at the heart of the Rajagopalaswamy Temple complex, and it is enormous — one of the largest temple tanks in Tamil Nadu. The tank is surrounded by stone steps on all four sides and enclosed by the temple's outer walls, giving it a cloistered, almost private atmosphere despite its size.
The best time to visit is early morning, when the water is still and the main gopuram casts a clear reflection across the surface. During the Brahmotsavam festival, the temple deity is taken out on a float across the tank in an elaborate procession lit by oil lamps — one of the most photogenic temple rituals in the delta region. Outside festival season, the tank is a peaceful spot where locals wash clothes and children splash around in the shallows.