Hi. I also found snails in my tank about a month ago(2), and they have not been bothering my tank. However, snails can reproduce very easily because they are neither male nor female. They can produce a lot at a time, & it would not be good to have too many of snails in your fish tank. I think you should keep up to the most 5 and no more, and if you start seeing more, I would remove most of them from your tank.