Batti is famous in Sri Lankan folklore for its singing fish. According to tradition, between April and September a strange noise – described variously as resembling a plucked guitar or violin string, or the sound produced by rubbing a wet finger around the rim of a glass – can be heard issuing from the depths of the lagoon. The “singing” is allegedly strongest on full moon nights, though no one knows exactly what causes it. The most popular explanation is that it’s produced by some form of marine life – anything from catfish to mussels – while another theory states that it’s made by water flowing between boulders on the lagoon floor. The best way to listen to the singing is apparently to dip one end of an oar in the water and hold the other end to your ear. Kallady Bridge is traditionally held to be a good place to tune in.