A fishing rig testing device (1) and kit of parts comprising a plunger (2), a water reservoir (3) having an open end (3b) for the ingress and egress of water, and a plasticised moulding (4) at the open end (3b) of the water reservoir. In use, the device mimics the inhalation and exhalation of a fish and allows the suitability of a fishing rig to be tested.