Fig. 2. The transition between alternating and synchronous pectoral fin coordination during steady swimming in the blue damselfish Pomacentrus pavo at a critical swimming speed of approximately 4 BL s^-1. This gait transition occurs rapidly, within 1-2 fin strokes. Asynchronous swimming (left panels) is seen from 0-33 ms, then is partially out of phase during the transition (33-67 ms). Mostly synchronous locomotion is seen from 83-150 ms (right panels).