Kick Ich is useless...don't waste your money! Sorry, I know it would be a nice quick fix, but I don't know anyone who's used it that's had any success.
Your very best bet at this point is to move the fish to an alternate tank and do hyposalinity. There are some very good articles on this and it will certainly help the situation quickly.
Keep in mind that ICH is usually the result of some type of stresser. The most common is temp changes in the tank. Most tangs..and saltwater fish in general, do best when you keep the temp swings in your tank to within 2 degrees...so if your highest temp of the day is 80 degrees, set your heater so as not to allow the temps to drop below 78.
Food, or lack of proper nutrition, can also be a stressor. Tangs are herbivores by nature and the bulk of their diet should be vegetarian. Be sure you're feeding a quality veggie in a clip (many of the "sushi" types have too much gelatin which is used to hold it together). When feeding, do feed a good quality herbivore frozen food. My favorite is Ocean Nutrition's Formula 2. Feed this to the tank first so your herbivores will fill up on that, then add your meaty foods. Although there is much controversy to this suggestion, I firmly believe in adding a drop of garlic to the food daily. You can buy supplements at your
LFS or simply use a garlic press to squeeze a clove and make your own! This feeding regime will not only help keep ich at bay, it will also keep your tangs from developing HLLE. Good luck and let us know how you make out!
