Okay, I'm adding this so that you do not lose ALL of your fish.
GET THE FISH OUT OF THE DT, ALL OF THEM
Put them in QT, do hypo or copper (not sure on your fish types if copper is okay for all of them) and leave the DT without fish for at least 6, better 8 weeks.
Read every one of the articles melosu58 posted and get those fish on the right track before the next outbreak kills them. Then, re-read them, save them as bookmarks and keep reading them during the treatment time so you won't be tempted to put the fish back too soon.
I could be nice and say try this or try that, but that is how I lost all but my 2 clownfish. I did hypo with them for 6 weeks and they are healthy, and ALIVE.