I used to have a large blue gourami that got an ulcer and it didn't collect a fungus up, just swelled up and was a bright pink compared to everything else. I read about a couple different methods for treating it, but none worked. I just went back to using a multi-purpose medication after a while, Aquarium Science Multi-Purpose, and after a few months, the ulcer eventually went down.
And as for your cory cat, I realise I'm a bit late, but I think it had velvet disease, which is like white spot, cept harder to treat.
Once again, you could've used Aquarium Science Multi-Purpose, which would've helped kill some the fungus off. If it didn't look any better in a few days, you could've caught your cory cat in a net, not taking it out of the water, and lightly scraped away at the scales with the fungus using a pair of tweezers or a needle. Yes, it causes some stress for the fish, but I've had it work with my betta's and on occassion, goldfish and a silver dollar.
In future, if you can get your hands on live food for your fish, say from a back pond, that can help bring you fishes immune systems up and help them fight off diseases, because of the organisms living in the water.
Good Luck with your gourami, hope it pulls through.
