Here is an updated picture: I didn't mean to imply the salt 'dissolved' the fins. However he was in a stable but not great state for months; and after a 5 days with salt this is his current shape:salt doesn't cause fins to dissolve.
post some more pictures of the fish
treat it with copper or malachite green. copper will kill shrimp and snails but malachite green is a carcinogen (causes cancer) so avoid getting the malachite green on you
I removed him about a week ago from salt - i'm thinking i should give him another week or two before any sort of additional treatment. He is not happy with me after the salt bath so usually when i walk over he goes off into the 'shrubs'.