Turbulent In Tub Options

[moomooteo]

Hi All:
I have been using a 1200l/h power head to circulate water in my 3x2x1 tub. but i have being advise that the turbulent is too strong for the fish. But my fish seem to like to play with the jets and they purposely swim against the current, and then stop to be be blown away by the waves. They also like to get near the power head. My power head is placed at one corner of the tub and i am also using it to dissolve oxygen. I don use any air pump. For filteration, i am using a Jebao 915.

1. Is my power head too strong and any recommended flow rate.
2. If we don circulate water, the water is very still. Is such still water good for goldfish. As i know, if we make them exercise , it is good for thier development