Garlic will kill parasites, so that is always an option. I have not found that the liquid garlic supplements work for this purpose (great for getting fish to eat though). Fresh garlic or NLS Thera+A are the things I have seen do this.
Metro+ would be good, but any medication will help kill whatever it kills if the fish have it. Quick Cure for externals, maybe some Pimafix for fungus, and something for internal parasites would be what I would focus on.