For anyone's future reference, lemon juice works really well if you get it into the mouth. Tried this... Got a few little piles of dead gray tentacles. If you don't get it in the mouth, you just make it freak out and hide. They shrink up when you squirt them... Wait ten minutes, if it's shrunk even more and turned gray it's dead. If it's back, it's obviously not dead.
I hate hearing people say "it's only a $3/$5/$1 fish/shrimp, so it's ok if it dies, I can just get another." It's still an animal! All animals should be treated like they're worth $10,000.
29 sw: Damsel, shrimpgoby, pistol shrimp, waspfish
65 fw: Rummies, glowlight tetras, pencilfish, darters, ottos, f betta, goby, dwarf gourami, ninjas
29 fw: Chili rasboras, pygmy cories, P. Gertrudae