A few minutes ago, I glanced in my tank and was shocked to see my largest snail stuck inside the filter intake! For some background, he is in a 29g freshwater tank which recently finished fishless cycling (I've been adding fish food to produce ammonia). There are no fish in the tank yet. The snail came in on some live plants I added to the tank a few weeks ago. I don't know what kind he is.
Anyway, at the moment, his body is inside the filter intake and his shell is outside; I know he's alive because through his translucent shell I can see the normal movement (looks like he's cleaning the inside of his shell or something). I turned off the filter and took the intake tube part off, and I even stuck the eraser end of a pencil in there in hopes that he wasn't really stuck and that he would retract into his shell when I touched him, but he really seems stuck. If anyone has any ideas of getting him out of there, that would be really helpful, but at this point I don't know if there's much to do (I also think I may have damaged him with the pencil).
Would it be more humane to euthanize him, and if so, how?