Video of a Robofish experiment (plan view) in the test tank (width x length x depth: 86 x 81 x 5cm). Before the start of the trial we placed 10 three-spined sticklebacks and a robotic fish: “Robofish”, in the enclosed refuge (upper right corner of the tank on the video), and left them for 2 minutes. At the start of the trial (and after 2.5s on the video) one wall of the refuge was raised remotely by fishing line. Robofish was then activated (after 4s on the video) and moved along a standardised route, and can be identified from sticklebacks as it is the first fish to move its entire body from beneath the refuge (judged from the viewpoint of the camera). Soon after Robofish made the first of its 90° turns, the sticklebacks made a sharp turn towards the lower side of the tank. The trial was stopped when Robofish had returned to the refuge.