The new snail I got from petsmart was really energetic and active, far more active than the two blue mysteries that I got from my LFS, and I was hoping that it'd survive, but now it's hiding in its shell, hasn't moved for a few days and is producing stress slime. I'm hoping it's not quite dead yet, but I don't know why it's stressed.
Water params are still fine, I've added a couple of ghost shrimp in the hopes that my betta would chase those instead of trying to nip bits off the snail, and I put a root tab in to help the plants but those are the only two things that have changed. Tank temp is still stable at 75F, water is hard but the same water that has been in the tank all along. I'm baffled, the petsmart fish lady is baffled (to be fair, that's not hard) and the guys at the LFS are all baffled as well. I think I've eliminated a poor supply, and I think I've eliminated shock from the transfer (the last two were drip acclimated for extra paranoia) I don't know what to try next short of completely breaking down the tank and replanting it, which I really really don't have time or money for >.<
I just feel really bad for this last snail. It seemed so active and healthy.