Fig. 1. Diagram of a fish tail illustrating the placement of a differential pressure sensor (1 cmx1 cmx1.25 cm) to measure swimming speed through the measurement of tailbeat differential pressure. The sensor was mounted on one side of the caudal peduncle at the position of the second last vertebral centrum, approximately 2 cm anterior to the base of the caudal fin rays and approximately 1 cm dorsal to the vertebra.