The video only very vaguely describes how this robot works. I totally agree on the point that we may underestimate fish (and snails too!) but the fish is not "driving" the robot. A robot is a machine that moves automatically. Therefore, this is not a robot that is being "driven" , it is a machine.
You may wander why I have put the word drive in quotation marks. This is because I believe that, by definition, the fish cannot drive the machine. The fish has not been taught how to drive, it hasn't learnt the skill, it is merely the fish moving and a sensor detection the movement that triggers a signal to a microcomputer that further identifies which motors to send current to. The fish just wants TREATS !!! and swims in that direction to get it.
Don't get me wrong, this is amazing technology but the praise should not go to the fish, many on here will disagree, but I think the real cool thing here is the AI.
Also, surely we must all agree that putting the fish in a small container, especially outside, is extremely stressful and can cause disease?