Formalin is the most effective treatment for Ich
Formalin is stabilized formaldehyde. It is a very effective treatment for Ich. You'll sometimes find formalin plus malachite green medications. This is even better! Follow the directions on the bottle. You'll have to use several doses since Ich can only be killed when they hatch out in the gravel and swim toward the fish host. Remember to remove activated carbon while treating with a formalin product..
From James 13 days ago