My purple tang got ich after being in my tank for 3 months with no new fish being added...
All I did was step up my maintainence and feeding regimen. I went from feeding once a day and hanging some nori every few days to putting in nori everyday and feeding 2-3x a day. Started soaking the food in selcon and the kents garlic stuff and within days (perhaps a week) the ich fell off and I have never seen it in my tank since.
With all that feeding, I have added a couple of powerhead filters and change them out every 3 days or so. I didnt feel my skimmer was able to adequately keep up with my input of wastes...
My fish are fatter then ever too
