This is what's written in Arthur Spiderwick's Field Guide to the Fantastical World Around You about the Nixies. Guardians of freshwater pools and streams, nixies, (also called naiads and nixes) are bound to the body of water in which they dwell. They are most commonly spotted alone and can be identified by the liquid continuously streaming from their hair and clothes as well as the greenish sheen of their skin. Nixies are amphibious and, unlike mermaids, they have legs rather than a tail. Nixies