Same advice as the others... you're probably on the low side of flow versus where you should be.
I started out the opposite way - when I put my 1st fish in the tank (O. Clown) I had too much flow and it was just getting hammered wherever he went. I rearranged the flow and he seemed much happier. Of course, I've rearranged the flow twice since that time, but I've still managed to give him his little corner of moderate flow that he seems to like.
Clowns do seem to just hang out in the corner of tanks. Once he gets used to his new home, I'm betting he'll venture out and start exploring. It took mine several months to do that, and now a year and a half later he's cruising the length of the tank, playing around overhangs, and generally going everywhere. But he still goes back to his "home base" corner in between adventures!