Naiads

Summary
Naiads were a type of water nymph who presided over fountains, wells, springs, streams, brooks and other small bodies of fresh water. They are distinct from river gods, who embodied rivers, and the very ancient spirits that inhabited the still waters of marshes, ponds and lakes.

Mythology
Naiads could be dangerous. They sometimes took humans who were extraordinary. They were also known to be jealous.