Could it be Fin Rot?

Hey guys! I found a nice home for the trouble-making guppies. But now, that poor red wag platy' fins seem a little bit clear. The other platy's fins are clear, but they have black running through them and the platy in question does not. The platy is on the bottom of the tank and has been all day except for feeding. Its kind of hiding under a root type decoration, I'm guessing to be away from the other fish. Could this be fin rot? There is nothing on the fishes body and fin movement isn't terribly fast when compared to the other platy, but it seems to be breathing a little bit harder. All other tank mates seem fine at this point. Any thoughts?

Oh yeah, and all water conditions are great. I've ran 2 complete tests today with perfect results.

He does seem to have a disease although I have no idea what kind. You could go through the blog section to try and identify what kind of disease it is. The blog is one of the older ones so you may have to search a little bit. Water changes and using salt seems to cure most diseases.

I have ghost catfish, platies, mollies, neon tetras and most importantly, snails. I assume I've gotta take the snails out? Can these fish handle salt (all except for the platies and mollies)?

*I know that platies and mollies like salt*

Mollies are sometimes raised in brackish water, but other freshwater fish should not be exposed to saltwater on a long term basis. Platies, especially young ones, have clear tail fins. Most develop color later, but some never do.

Ok, good. That checks off Fin Rot off my list. I must sound like a paranoid crazy person with all of these posts about what could be wrong with my fish, but being a perfectionist, its very bothersome to not know why something is happening. Thanks so much for all of your great advice!