The black one oozes around and up the walls and whatnot. The yellow one oozes about and licks the glass. I've been informed that snails usually lick the walls like that, which I actually remember seeing my boyfriend's dad's snails doing.
Why doesn't my black one lick the glass?
And why was my yellow one floating on the top of the tank this morning? I poked him and he sunk to the bottom, and eventually came out of his shell and went about business as usual. I was weirded out.
And why does the yellow one have a big air bubble in his shell?
And, the yellow one looks as if there's a huge crack around the shell at one point... and from then forward, the shell is bright yellow and algae free. Before the crack, it's all green/spotty ness.