You will see a lot of mixed responses about the proper thing to do when you have ich. A UV sterilzer certainly will help keep a clean tank from developing ich, but I think by the time it is visible, the UV wont be able to get rid of it (im not 100% sure on this, someone correct my if im wrong please).
As far as removing the fish, some people will tell you that you should remove then and quarantine no matter how big of a hassle, but I agree, this can be an enormous undertaking and quite possibly do more harm than good if not done properly.
Have you tried garlic extract with their food? I hear that can help. Also, is anything else wrong with your tank? Some parameter or a recent change... its rare if not impossible for a perfectly healthy fish to come down with ich it cannot shake on its own.
