I agree with Ron J. Hyposalinity is the best treatment in my opinion. You will need to use a refractometer though, instead of a hydrometer. The reason for this is that you'll have to get the salinity down to 1.009. Anything above that won't gaurantee killing the parasite. Most hydrometers just aren't accurate enough to use. I'd recommend keeping the salinity at that level for at least 5 weeks from the time you see NO signs of Ich. Steve-S is a great source and has posted and responded a lot on RF about fish health. The only problem with hyposalinity is that it'll kill any inverts, snails, corals...etc. in your tank. If you're able to do this in a QT tank, that's the best approach. Tangs are notorious for Ich, as RonJ mentioned. Good luck and let us know your results!! Oh, one other thing I'll mention from past experience. Don't attempt to do too much, too quickly. As an example, there are a lot of supposed remedies floating around out there. I made the mistake of trying a couple of them over a short period of time and ended up stressing my fish so bad they died.
