The fish market at Ramanathapuram handles the catch from the Gulf of Mannar fishing boats and is worth visiting early in the morning when the boats come in. The range of fish, prawns, crab and shellfish is excellent, and this is where the town's seafood restaurants buy their stock. The area around the harbour has small stalls selling fried fish and rice plates at very low prices.
This is a working harbour town, not a tourist destination, and the atmosphere in the fish market is purely commercial and practical. If you are staying overnight in Ramanathapuram rather than pushing straight through to Rameshwaram, a plate of fresh crab curry here is one of the better reasons to linger.