The pet store Sprite

Violet and Sprite discover that there's something fishy going on at the local pet store. People are disappearing from the town, and the fish at the pet store's tropical section look oddly like the people who are missing! Sprite suspects Aquamarina the Water Sprite. And when Violet sees a fish that looks just like her friend Brittany, the clues all fall into place. But will Violet and Sprite get to the bottom of it before they're in too deep?