SO I have been meaning to chime in here. After seeing Duane's demonstration using Melafix for AEFW, I decided to go ahead and use it in my QT for a couple fish that were having problems. While it did not save the fish, I did take care to note how all other animals in the QT were reacting.
As background info., when I QT fish, I have a lot of macro covered rocks, pods, snails etc. in the QT to give the fish the best possible environment in which to recover from shipping and handling. I have a skimmer and UV on the tank as well as auto top-off. SO when I placed these fish in the QT, there were many animals present. MANY MANY snails and pods, mini-brittle stars etc.
I then felt compelled to dose melafix and that's where Duane's demo came to mind. I knew it would not adversely affect corals, so maybe I would leave in everything and dose the tank, which I did. The fish struggled for about 3 weeks and never recovered unfortunately, but the interesting thing to note, is that the tank inhabitants all fared well also.
I doesd a capful of melafix each day (40g tank with skimmer and UV off) for 2 weeks. The snails, pods, macro, SPS, LPS, palys, stars, and macro all did just fine with this rather agressive Melafix dosing. I am amazed really, and this again points to the "herbal" nature of Melafix. WHy it kills AEFW and red bugs, but not all these other sensitive animals is beyond me.