Yea, dont worry too much about fish, if they get hit by the jets they always find calm spots in the water.
The other part is play around with your jets, find a stream that wont aggravate your corals. Like Mesh said, they wont open up if they have too much flow so you can use that as a short term indicator. if they start to close, too much flow for that coral, move him, change the flow, or flow direction
:)