hey guys, didnt know where to post this, hope here will do. anyway ive pick up snails from a peace of driftwood from the lfs, they are really small at what i take as full size as i havnt seen any over 3mms, most are see though, and what i take as the older ones are a brownish colour, so any thoughts as to what there name is and how to get rid of them?? they are in my bristlenose fry tank,