Search for the Silver Shell — Robin Yardi

Full of magic, mermaids, and friendship, Coral Keepers is the perfect epic underwater early chapter book series for newly independent readers!
Pick a book. Grow a Reader! This series is part of Scholastic's early chapter book line, Branches, aimed at newly independent readers. With easy-to-read text, high-interest content, fast-paced plots, and illustrations on every page, these books will boost reading confidence and stamina. Branches books help readers grow!

More than anything, Princess Finn and her friends, Moon and Link, want to become Coral Keepers -- mermaid magicians sworn to protect the Queendom of Anjeea. Finn is a shark magician, but she is struggling to pass her shark-magic test. And now, an evil magician named Rozaro is plotting to steal the throne! Only the power of the Silver Shell can stop him. Can Finn master her shark magic, find the magical shell, and protect Anjeea?

With engaging black-and-white artwork on every page, kids won't be able to put down this magical, underwater adventure!