I picked up a new apple snail today, I think it's a bridgi. Anyways, he's been fairly normal, except for the last couple of hours he's been laying on the bottom of the tank, looking like he wants to come out of his shell, but someone is biting him or something. He'll open about 1/2" and poke a tentacle or even an eye out, and then jerk shut again. What could be the issue? I wonder if maybe the little acara bit his tentacle and every time he pokes it out, it twinges or something so he jerks closed again. Any ideas?