Are you sure he does not have ich? That 2 day treatment just isn't adequate to treat ich?
Can you put this fish in a quarantine? There isn't much that can done or suggested for treatment in the display.
Jerry, rather than argue the point about feeder goldfish let me quote Robert Fenner, a well known, professional, published aquarist. Basically, feeding goldfish to lions is a common knowdege misnomer in the hobby:
"I'd like to mention another type of "disease", environmental; from comet feedings I've seen time and time again: Death from "gut blockage" in particular in lionfishes and their relatives. There is a tendency for feeder 'skulls' (crania) to block over the opening from the stomach to the intestine in this group. From necropsying enough scorpionfishes to fill a fish store I would guess "feeder blockage syndrome" as their single largest source of mortality."