So far I have only found 2. However, I read that these are pests. I have had my plant and substrate for almost 4 months now and this is the first time I have seen them. Are they pests? How do I get rid of them if so?
Most likely there were eggs on the plants. Looks like a ramshorn snail. They don’t eat plants, so you don’t have to worry there. (Only the parts that are dead or dying) they won’t overpopulate unless you are over feeding. You can get rid of them, but you don’t have to. I keep them in all my tanks because I feel like they have many benefits. (I put mine in on purpose, so I guess it’s a bit different when they come uninvited)
small snails are good at cleaning algae off of small leaves on plants. Larger snails like neuritis generally are too big to clean algae off of small leaves. In my tank I have 2 neuritis that keep the glass and filter clear of algae while the small snails work on locations the nerites can't reach.
I also leave them in my tanks unless too many start showing up. I you watch how much you feed your fish you can keep them under control for the most part.