Dragon Girls #8: Phoebe the Moonlight Dragon by Maddy Mara
From Scholastic Paperbacks:
The Night Dragons are united in friendship and in a shared mission: They must save the Magic Forest from the evil Fire Sparks. They are out to ruin the delicate balance that exists between night and day - and only the Night Dragons can stop them! Phoebe has a special task ahead of her. She must spread her wings and rescue the Dreamlets, magical creatures who create dreams for all the forest animals. Can Phoebe overcome her fears to help save nighttime?