Since the 18th Century, Tamil fishermen have claimed to navigate by the mysterious music of the singing fish of the Batticaloa lagoon in eastern Sri Lanka. The fishermen's ancient name for the creature is Oorie Coolooroo Cradoo (crying shells); scientists believe that the underwater choristers are some kind of fish. But, after 30 years of civil war and the ravages of the tsunami, does any evidence of this strange nocturnal chorus remain?