A bit of an update:
After more than a day in the tank, I'm starting to lose hope for my LB. It can't swim properly, or keep itself upright (most of the time I see it laying on its side). It used to run off whenever it saw anyone near the tank, but now it doesn't even have the energy for that. I had to chase off a bristleworm that tried to make a snack of my LB. Its tail and fins are all frayed too.
Should I keep at it and hope my LB will recover? Or should I just put it out of its miseries?
-Rich