Strange Little Snails

They look like baby ceriths. I was planning to get some hermit crabs. Would the hermits bother them?

 

That happened to me before. Did you get a new plant recently? Because when I did, a few weeks later I noticed several little snails in my tank too. Apparently they live in the plants when you get them. They are not a good species to have. They can take over your whole tank community. I would post a picture of mine, but every time I try I get an error. But if they are about 2-7mm long, then theyre probably the same thing. Also, is your tank salt or fresh water?

 

Saltwater.