Since I use a powerhead sitting on the bottom, I have an option to point the water jet in different direction. I currently point it down towards the bottom to minimize water flow.

I am wonder if I should use the water jet to create a steady water current in the tank so that the goldfish can do some exercise. Yes, like an underwater treadmill. Will the treadmill make them healthy or really stress them out?

My goldfish are fantails, so that cannot swim too fast. So the treadmill will be set a low speed. What do you think?