Day 3:
Neptune seems to be holding up, though his moving around the bowl has reduced, possibly due to the effect of the meds. He's one heck of a socializer and if any one of us come near his bowl, he's all flashy and ready to talk. The clumping of fins has eased a bit, so that's a good sign!
My wife gets special attention from him

and he's ready to listen to whatever she says. Just this morning, she asked him to turn sideways and show her his fins and he actually did!!
I guess the rot has been arrested though we still kick ourselves for listening to the Petco nitwit team leader and delaying his meds. He would have been in better shape, if only...
We have started feeding him 2 pellets daily as against 4 every other day. The pellets are gone in less that 10 seconds, so he's good there. Judging from the slow recovery, my guess is he'll have to be on for at least 3 weeks as opposed to the original 1 week.