This video captures the movement of the knifebot, a bio-inspired underwater robotic system designed to swim using an undulating fin, similar to how fish glide gracefully through water. The experiment was conducted in the wave flume at the FAU SeaTech Laboratory, where the knifebot was placed in a steady flow environment. Fluorescent dye was released into the water to visualize the complex flow patterns generated by the fin’s oscillations. A camera positioned beneath the tank recorded the fin’s motion and the resulting fluid dynamics, revealing the harmony between robotic engineering and natural aquatic propulsion.