Crew;1066106 wrote: It's important to start by understanding what Ich is - a parasite. The best way to fight is is to fight conditions where it thrives, weak or hungry fish with poor immune systems. If you want to try and treat in your display, you can try and simply eliminate the conditions instead of using medication. This is the path that I would try since you are upgrading in 6 months so having a QT for half of that doesn't seem terribly feasible.
I would start by soaking all of your foods in Garlic. Personally, I use Garlic Guard. I soak all food for 10 minutes before feeding. Not only does it help raise the immune system of just about everything in your tank, but it will really help push an appetite in your fish. This is important because fish that are sick generally have a suppressed appetite, which only makes the situation worse. If you can continue to get your fish to eat, they are more likely to fight off Ich on their own.
Also, maybe try a vitamin? I use Seachem Vitality. Same with the Garlic, I soak for about 10 minutes before I feed. I find that it helps keep my fish colored up, which is a sign of a healthy fish.
Then, once you upgrade tanks, you can tackle medicating them while they are in a tank without live rock or anything that the medication might "contaminate".
While neither of the things I described are "medication", I find that it will probably help your fish fight the parasite on their own. Plus, you won't hurt any of the inverts in your tank with this method (where anything copper based will).
Good luck!