Hi I have four small fancy goldfish in my 20 gallon tank currently and one is sick. I just died 3 days ago from the same disease. There are no real symptoms except that they float to the top and lie on their sides. Their breathing is shallow and their color has faded. (1) What is this? (2) How do I get rid of it? (3) How do I prevent my other fish from getting it? Water Quality: Nitrites-perfect Nitrates-not great but in safe zone everything else is fine too. I've added lots of aq. salt and Novaqua and Aquaclear? conditioners with every water change (which I've been doing frequently; about 1/3 each time.) Please help, I've already lost my favorite red/black oranda.