Fin Rot Or Something More?

I just got an albino corydoras yesterday night from Walmart, and I picked out the lil one w/no top fins because I didn't think about it too much and just figured he'd been picked on or something (which corys don't do to my knowledge, so who knows). looking at him closer though and posting on the cory forum I started to think he possibly has fin rot. He's been separated out from my tank and here are some pics. I never pay attention to ph so can't give you that (sorry) but this problem happened before I got him. He was being kept in a warm tank as there was a betta in it. He stays still for long periods of time/tries to hide. Then when he does move he flips out and goes zooming everywhere, a lot of times skimming his sides along things. PLease help!
His two top fins are gone, his back fin is about half gone, and he has little stubs for front side fins. Also his gill area is red (not sure how normal this is)

oh bless him , he doesnt look very well , i would get something to treat finrot asap . is he eating ok?

I agree you need to find something for finrot and hope it doesnt eat into his body. Finrot is a slow disease to see any healing from and will take a few weeks to see the growth coming back.
The red of the gills is ok as he has light gill covers.
Just really clean water and once you have run the course of finrot meds and the rot seems to have stopped try using melafix and pimafix together just to keep the area from re infection.

Thanks, I've started treating using maracyn II and I'll make sure his water stays really clean, unfortunately my hospital tank doesn't have a filter, as it is just a 1 1/2 gallon thing I use as a travel case normally. I'll look into those other meds for afterwards. Would you recommend doing 2 five-day treatments or is 1 probably enough? Also I put some of an algae wafer in his tank last night and it was almost all gone when I woke up so I'd take that as a very good sign! Thanks again Louise & Blackangel

Do 1 course to start with and see how he looks after it. I dont think you can do water changes while using the maracyn so do a large water change before adding and make sure theres plenty of air going in. The water if you didnt know does go cloudy so dont worry about that.
Feeding some protein now and again will help his immune system, so bloodworm and maybe brineshrimp or something that will sink to the bottom.