*Sorry if i repeat myself through this, i've had a few too many rum and coke's. However my advise is sound and solid, as i follow my own ramblings very well. Ask anyone who has been at my house, less is more!*
I have learned through trial error and massive headaches, sometimes it's best to allow the fish to recover and heal on it's own. Give it a healthy environment, plenty of food, and it will usually recover on it's own. Sometimes however it won't. I have 3 tangs in my tank, and all 3 have had ich at some point. I keep them well fed and the tank stable, and all 3 have recovered, and thrived. Sometimes stress and a massive change in the tank will cause more harm than good. Clowns (especially tank raised) are extremely hearty, give it lots of food, and keep your tank stable, and i'll bet it'll recover in no time.