I had a pest snail outbreak from my dry first plant....those things look like little pearled teardrops and practically double population by day
I now keep four assassin snails and have never had another infestation since the first time
I love my little assassin snails, they are busy in the evenings and eat protein based food. I use a sinking pellet to make sure that they get some. On the rare occasion I lose a fish, the snails clean up the body so I don't have the ammonia spike. (Except algae eaters, they won't touch them)
They aren't prolific breeders-you actually need both a male and female to lay eggs, and you can see the eggs once laid so if you don't want them you can take them out-they lay one at a time on plant stems and they look like little square packets