Some see snails as a pest. I think snails are a valuable 'employee' of the clean-up crew. They eat algae and those bits of uneaten food and waste. They are part of a natural aquarium. Oh they might not fit in with plastic plants, garish gravel, and treasure chest/diver bubblers....but in a naturalized planted tank, they can be an asset. Byron first clued me in to Malaysian Trumpet Snails. So I ordered a dozen. I now have hundreds in a few different tanks! I 'inherited' a few Ramshorn snails from some plants I got at a club meeting auction. I now have dozens working in some tanks and daphnia bins.
Only some snails will eat plants as most prefer rotting plant waste and other unmentionables.
Now having written the above, if there is too much (waste) food, snail populations can get excessive and become undesirable in a display tank. There are traps and I wouldn't, but some might resort to chemical additives to kill them. Just remember that anything in the water gets into your fish through osmosis. Chemical treatments to kill snails might not kill your fish, but I don't think they're good for them either!!!
