Track + Fish

The track sits above the fish which the fish run on. The track is there so that the fish are able to move around freely within the tank. The motor consists of a trans-axel which moves the wheels and the differential which allows the string which connects the fish to be raised and lowered. The outside of the track has a perimeter which allows the motor to be move around the outside.

This is a printer head  Mechanically it is similar to our fish moving system. I wish to model our system to work similar to this.