The Naids are divided into various sub-classes: krenaeae (fountains), pegaeae (springs), eleionomea (marshes), potameides (rivers), and limnades or limnatides (lakes). They are intimately connected to their bodies of water, as their own existence seems to depend on it. If a spring dried out, the Naiad presiding over it might die.
Many Naiads live in the Canoe Lake at Camp Half-Blood and looked with curiosity at Percy Jackson's arrival. When a Nereid visits Percy in the Mississippi River, she tells him that the Naiads are sustaining her life because the water was too foul too stay there long.
The Naiads help to push the boats upstream when Percy asks them. While he and Zoë Nightshade were in the canoe together, a Naiad splashed water at Zoë and said that they had never forgiven her for becoming a Huntress of Artemis instead of staying with the Hesperides.
|“||You're not so different from me, demigod. Even when I'm out of the water, the water is within me. It is my life source. I hope you find a way to rescue your friends.||”|
There was a Naiad that lived in the river near the Triple G Ranch. Percy had planned on using the river to clean the flesh-eating horses' stables but she didn't want her river to become polluted again, as it did when Hercules was given the same labor. The naiad was prepared to fight to protect the river even if Percy was the son of Poseidon and could easily beat her, but Percy didn't want to push her around and refused to fight, surprising the naiad. The naiad reminded him of Rachel Elizabeth Dare because she was asking so many questions it felt like she was throwing rocks at him.
In order to avoid the river pollution, the Naiad taught Percy how to summon seawater to clean away the dung by throwing fossilized seashells onto the ground, claiming that water used to cover everything and the sea follows Percy wherever he goes.
Percy later remembers the Naiad's words while trapped under Mount Saint Helens and uses what she taught him to save himself.
- Like Artemis, the Naiads were seen as the divine nurses of the young and the protectors of maidens.
- Piper states that they get on very well with children of Aphrodite.
- A moon of Neptune was named after this species.