ewwwww! I will NOT squish Gary! lol I've removed all gravel and rocks, so it's just a bare bottom for now. Thanks for the heads up!Of course it's name is Gary, lol. It looks like a pond or bladder snail, a general term for pest snails in that shape. Mine are darker brown...except when small. Watch out for jelly-like egg masses on anything; glass, substrate, decor, plants, filter tubes. They are almost clear & may be quite small. You can scrape them off w/a fingernail & vacuum them out but there will probably be more. You might want to remove (or squish) Gary or you may have a lot. It's time to be tough & observant. Feed very lightly, the more food, the more snails.
I'll keep a lookout for the egg masses but I am pretty sure that Gary left with the rocks. I'll look behind the one filter tomorrow for sure. Thanks again. You're an angelStill you need to watch for small egg masses. Like a flattish gob of tiny firm-ish slimy stuff. As small as say, a peppercorn up to a 1/4+ inch.
Get tough! or you will have a snail tank. I don't know how long a snail may "hold" fertile eggs before laying them. IME you only need 1 snail to have many.