Ornanda fin rot

[Flossie]

My grandma has a large Oranda goldfish that appears to have finrot. Should I treat him in a qt or in the display tank? And what should I treat him with? Pimafix and melafix? Will this harm bb??

 

[Lowryder]

I have had luck with melafix fixing rot. It also makes your tank smell nice during the treatment. You can treat the main tank because it will benifit the others as well. I don't believe it disrupted my bacteria in my tank. Since your fish is sick you will be testing more often anyway so you will notice. Now, I can't say which is better because I have only used melafix