They are resistent to ich. Good water conditions help them avoid it. I don't qt this species and have never had a problem, but if you need to, in order to get ich out of your tank, qt them apart from your other fish in a non-treatment tank [need not be large] and order online pods for them. Reed Mariculture [Reef Nutrition] is a good source, and one 4 bottle order will easily see your mandarin through a 6 week qt. Order the Phytofeast to keep your pods alive and eating during this period and drop in a bit a day. Your mandarin will not be unhappy about this arrangement. As long as he can eat 12 hours a day, he's happy.