Movie 1

[(00:05 s) Knifefish swimming in laminar conditions. (00:16 s) Fish swimming behind a large and small fixed cylinders. (00:36 s) Fish swimming in laminar, behind the small fixed cylinder and behind the oscillating cylinder. (01:15s) Fish showing passive movements in the wake of an oscillating cylinder. (01:31 s) 3D printed fish model in both the wake of a fixed cylinder and the wake of an oscillating cylinder. (01:49 s) Instantaneous vorticity fields of the ribbon fin of a knifefish swimming in laminar conditions, behind the fixed cylinder and behind the oscillating cylinder].