Thank you everyone for the advice and well-wishes. Arcturus is doing so much better! His fins are still tattered though it looks like the rot is clearing up. His breathing is normal and he is swimming around like a normal betta! It is amazing what good water conditions can do for a fish, and definitely makes me angry that pet shops (and this Petco is one of the better ones around, which is awful) make these animals so sick and stressed just because they don't have time/energy to care for them properly.
I will take him out of qt on Tuesday or Wednesday. He's been in green tea for the last several days so I haven't been able to see his color at all. I've ended the tea treatment so now I can get a better look at him, but I can't wait to get him out of that boring 1 gallon qt tank and into his decorated, well-lit 2.5 gallon. I can't wait to see what his pretty copper color looks like in decent lighting; he looks so brown and boring in the qt tank!
I'm so sorry you lost your fish Aluyasha, stores should not be allowed to sell fish if they can't take proper care of them. >:(
BlackBerryBetta: How is your fishy doing? The first few days were so stressful because every time I went to check on him/feed him/change his water I just knew that I would find him dead and I got this dreadful feeling that almost made me afraid to check on him. Now that I am getting near the end of his qt, I am just anxious to get him out of there! I hope your fish makes a full recovery and gets to enjoy the good life outside of qt soon!