The Pet Store Sprite: A Branches Book (Pixie Tricks #3) - Tracey West - Bog

Violet, her cousin Leon, and the Pixie Tricker Sprite have a serious problem: the fairy they are dealing with now is a water sprite named Aquamarina, who is not only messing up plumbing all over town, but has made a home in a fish tank at the pet store, and has turned anyone who sees her into fish--in the water she is powerful so the three fairy-hunters must come up with a way to trick her onto dry land where she can be overcome.