ick treatment

Question
Hello,
I have been treating my 55 gal tank for ick (Rid-Ich) for 13 days now and my infected fish only has 2 white spots left(like salt, white bump) on his tail...there were alot more 13 days ago....My concern is he no longer eats, just sits in bottom corner all the time.  I have 2 other fantails still healthy...tank is only month old, still cycling.  30 % Water changes every few days keeps ammonia down to 0.5 at best, with added conditioner and bacteria each time.  Temp is 70 F.  Aquarium lights shut off constantly.
My only concern is the health of my fish (each one is 2 inches) and if he's going to make it through this ( his bottom sitting worries me) Is there anything I can do to help him?  Thank you for your advice.

Answer
Add an additional oxygen source while you are medicating, you can also probably do a small water change and not add any more medication but still do not use your filter, this will cut down the medication in the water and possibly make a difference if the length of treatment is affecting him. You can also add regular aquarium salt, goldfish do really well with a small amount of aquarium salt in their tank. It also relieves stress and adds minerals to the water that are beneficial. How is your tank temp? Some people heat up the tank to speed up the ich lifecycle, this can also take its toll on a goldfish as they prefer cooler water, if you did turn up the heat I would start dropping that a couple of degrees an hour, that may also help your fish. Best of luck...