Man, he looks bloated!

I hardly see dropsy on a slender fish like a shubunkin, and its tough to see such a slim fish blow up like that.
Kendon, just email me your addy, there is no money needed. I have a jar full of medicated food that I can't all use up within the expiration period. At least I hope not, otherwise my fish are in big trouble...

Its only a few cent for the stamps, so please, don't worry about it. Its "on the house"...

About the yellowing, I am wondering if it is a calico "symptom", so to speak. The calicos have a different makeup of coloration, with all the color pattern involved what makes a calico. Maybe the yellow just looks so weird because it is the underlaying color to make up some of the blues or whites in a calico, and you usually wouldn't see it that much since the scales are always flat.

Otherwise I never heard of the color yellow showing like that in a dropsied fish.
Dropsy is a long term thing to deal with, and you might not see the swelling going down right away. Might also be that the Furan just isn't strong enough. Melafix sure won't do the trick, that stuff is even weaker. As for the salt, you don't have it permanently in the hospital tank - you only dip the fish in it, and then put him back into salt free water? The epsom salt really should be in the hospital tank all the time.
Usually mechanical and biological filtration works hand in hand, and a lot of the mechanical filter media is also considered biological, since it also holds the bio bugs. The pondmaster isn't the greatest example of such filtration, but there are plenty of other filters out there that do an excellent job - mechanical and biological. I never would use biologial alone, since those big waste pieces need to be picked up and collected by something, otherwise they are just going to end up in the pond over and over again. If you leave the mechanical media out of the filter, the biological media holds all the waste, and some of that media just isn't made for that purpose. The pores are very small in biological filter media, and are being clogged up very easily by waste. Waste that otherwise wouldn't even reach the biological media, if the mechanical media would have grabbed on to it. Clogged up pores prevent the beneficial bacteria from "breathing", and suffocate it. Hence making it useless.