Interesting! I was wondering mostly about the vehicle. Fish were placed into a tank that rested on a mobile platform. The tank had a small volume of water in order to restrict water movement as the platform moved.

It seems that there was a camera mounted above, and a computer (a Raspberry Pi) could analyze both the orientation and location of the fish. As you would expect, when a fish faced outward and neared a boundary, the platform would move in that direction. When the fish was facing inward, or in the middle of the tank, no movement was created.

I have a Raspberry Pi, and I need to think of my first use of it. I wonder if my boys would like a goldfish. = )