I managed to get rid of mine. They never bothered the yellow tang, but they loved the colwns. Since the clowns are so slow and easy to catch, i just picked them off manually. Every morning I'd check the fish with a flashlight. If there were some isopods on them, I'd prepare a freshwater dip and dip the fish for about 30 seconds. The isopods would jump off immediately. There were a couple of occasions where the pod still stayed attached. Then i would put the fish on a wet paper towel and pluck the pod off with a pair of tweezers.
I believe that I got about 10 out of my tank.
Just remember to make the freshwater dip the same temperature as your tank.