I did lose fish and struggling to keep my puffers eating at this point, an episode after a water change seemed to kick everything into high gear and that was when I realized that maybe ich can be managed but unexpectedly can rock your water world.
My goal is to make my tank Ich free not sure if it's possible but from everything I have read I think it can be, between QT, tank transfer methods and diligence there is no reason it can not be. My fish of choice at this point puffers are sensitive to coppers so copper is out of the question as a quick fix even though I am not running a reef tank. We also really like tangs. we added a Naso Tang super sweet lots of personality and somehow has seemed to be impervious to all the bad things going on in the tank. We had also added a Powder Blue that may have been our biggest downfall, it was small but so active and I think it was stressful to the rest of the fish prior to the water change incident causing a small ich outbreak all by itself.
The current plan is to transfer all my remaining fish a Dogface Puffer, a Porcupine Puffer, Naso Tang, yellow tang, Blue Hippo Tang, small long horn cowfish and a pajama cardinal to a QT tank for Hypo and leave the DT tank fallow for three months after going Hypo in the QT tank for 6-8 weeks I will then do the tank transfer method back out the the DT to match up with the three month Fallow period. I will then add any additional fish after adequate QT and tank transfer methods.
The big challenge, not sharing anything between any of the non DT systems and the DT, nets, buckets, filters etc.. seems like a lot of work but I think once everything is stabilized everything should get easier.