Be careful, the ich may have 'dropped off' the fish. Because ich is a parasite it has a life cycle and every 3-5 days the white spots on your fish will go. This means the ich has dropped off. A day later if the ich hasn't been cured it will return. Just be careful that this isn't what happened before you say 'Yay the ich is gone!'
Dont worry about it. There is a misconception out there about garlic that it is a cure all. The only thing I agree about it is that I do believe it will help with the immune system of a fish. This of course is IMO.