Well I tried minocycline. The outbreak wasn't too bad as only one blister broke open this time. Tough to tell whether the Maracyn 2 did anything since it takes awhile for these things to heal. He had 7 days of minocycline.
I'm going to keep him in the hospital tank, do a large water change, throw in some carbon to clear all the meds out, and in 48 hours try the Neomycin for a week to 10 days. Am ordering doxycycline. Have read that baytril may help with this, but I'd need to call my vet. She gave me a script before for that even though it wasn't effective for a rainbow with myco. I have some oxytetracycline food I may feed him while he's on the neomycin if he eats or I may wait for the neo treatment to end. Not sure if I should mix those two antibiotics even though they won't be mixed in the water column? He is acting normally in the hospital tank throughout, but not eating much which is pretty normal for him when confined in a 20G.