Up until yesterday, ammonia had been low... :/
I have peppered corys. I'm not a fan of returning animals, especially if my fish has something contagious, because if they somehow have whatever it is, it will spread to the others at the pet store. I bought them at Petco, and I would hate to take them back there, of all places. (Mine takes pretty good care of their fish, but still...) And I get attached easily. :/ Also, in one of those articles you linked, it says if I test once or more a day and consistently do water changes, they have a large chance of making it through. I will dedicate to frequent water changes and tests every day until the water is stable. I was a dummy and read off of the aquarium directions, which states that 24 hours is enough time to run the tank (which I obviously know now is not correct).
As with the salt, I haven't added anymore since I did yesterday and I've done two large changes since.
I did NOT have a filter on my one gal (like I said in my first post, don't think I'm terrible. I didn't do a whole lot of research, but I'm much more educated now). I wish I did have an old filter, but I don't. I heard you can speed up the cycling process by adding a filter sock? What's that? Also, my neighbors have a 20 gallon fish tank with all sorts of fish. Would it be worth a shot asking if I can have some of their gravel to put in my tank? I heard that helps, also.
One last thing: looking through old (blurry) pictures of my betta when I first got him, it looks as if his coloring has always been weird (faded on the bottom and a little silver on the gills). I can't believe I never noticed it before. I'm starting to think that the silver is part of his natural coloring...though I have noticed a white-ish spot on his eye. I posted a couple more pictures of him on my DeviantART. You can find them here:
Silver gills by =twixie09 on deviantART and here:
http://www.deviantart.com/art/Silver-210318741. He has been swimming more lately (not just scratching) and eating more...maybe he's getting better? idk The corys seem happy as can be; they're making bubble nests and swimming around all the time.