Went into PetCo today because I was up at that exit and found this little halfmoon all curled up in his cup. I thought SBD and talked to the manager that was there. I told her that I rescue bettas and offered to take the fish because he probably wasn't going to sell anyway. She ended up giving him to me and now I'm hoping I can diagnose what's wrong so I can nurse him back to health (and later put him up for adoption...if I don't get attached..|D )
Here's a video of his behavior. Almost seems similar to what Alduin's issue was when I first got him, but this is much more severe.
I'm in the process of converting my poor goldfish babies (who passed away) tank into a rescue tank, but for now, I put in some new water and I'm thinking about adding a little salt. He seemed to perk up a bit when I added the new water, that's for sure. Anything I can do for him?