Betta stopped moving and seems not working. What should I do?

Most likely you would need to do nothing unless the robot gets tangled with the floating vacuum tube in its path or gets stuck in some tight corners. It will stop and turn itself into ERROR mode when running into obstacles it can’t free itself from or getting stuck. LED lights at the top backside of the robot will show the error modes and the robot will restart by itself in 20 minutes. In the event the robot gets tangled or stuck, you need to remove and relocate it or set it free from the obstacles in its path.