I had mollies that bugged my mystery snails until it died, then they ate it. - but I havent heard of anyone else having that so I guess I have agressive mollies...
Do you want to keep the snail or not? If you do than you're fine, if not then I'd recommend squishing it - your fish will think it's a nice treat.
i kept a hitch hiker recently snails all over the tank at the moment, its not a problem because i dont have any fish in it yet im sorting out the plants first. no feeding so im hoping some of the snails wont survive. but i might dose the tank with copper before i put fish in. (bad idea if you have fish in the tank already)
\i would get rid of it now before they multiply very quickly. if u do have a out of control little snail problem there is a treatment stuff to get rid of them that wont harm the fish, that is at most petstores
Just remove it. If you see anymore then just do the same. Have you added plants or anything new to the tank recently? They could have come in on a plant. If you overfeed your fish there will soon be an explosion of snails that you'll find hard to clear up.
Adding snails/fish to eat the snails will work but then if you don't like them there's not much point.