Well it's late for me ,early for most everyone else, but I'll do my best to relate my NTD exp with you. I'm still a newb in my opinion but I've had alot of sucess over the last year and have a healthy tank now. About 5-6 months ago I had NTD in my tank and I lost my neons, likely 10-14 total I didn't catch it and just kept replacing them when one died not understanding how contagous it was. Once I pinned it down to NTD and started reading up on what I could do it came down to the last six I tried to save. I didn't have a Q tank and regret to say still don't. I chose the hard choice of euthenizing the fish that had NTD since there wasn't a cure. What I watched for was a color loss in the red part of the fish. The first two or three I killed as soon as I saw it. I know it sounds creul but I didn't have any other option. After I came to the last three or four I just gave up. It didn't spread to my other fish and to date I haven't even seen a good source of what fish , other then tetras, that it can infect. So I just let it run it's course. I was left with one neon that managed to either avoid infection or developed an imunity to it. I left him as the lone neon for well over a two months then impulse bought 3 more neons to finish my tank stock off. So far after about a month all are doing well so hopefully the infection is gone and over with. (Note I did buy a new larger tank and cleaned everything very well before I moved them into it and later bought the new neons). I wish I had good news for you but I'm guessing even with agressive action on your part to stem the tide in your favor. You'll still lose most if not all of the neons. It's a horrible desease to have break out. It's also a prime example of why a Q tank is so important. My sympathy goes out to you mate.
-Neo Sithlord