I've just done a water change and had my daily inspection of fish and noticed three out of 6 fish have tiny white dots on their tails and fins, which I believe to be ich. What do I treat the tank with and how do I treat ich in a 6x2x2 tank with two stingrays in it? How at risk are my stingrays from getting sick, and are there any issues treating the tank with the rays in there? Tad worried. 
