Mr. Fangtooth worked in the Trident Academy cafeteria. He constantly had a grumpy look on his face, and the mergirls always tried to cheer him up, usually without success. Recently, he had saved them from a shark, and they’d found out he was a retired colonel from the Shark Patrol.

“Hi, Mr. Fangtooth,” Echo said. “What was it like being in the Shark Patrol?”

Mr. Fangtooth wiped the lunchroom counter off with a black dragonfish. The fish’s open mouth scooped up tiny scraps. The fish burped, but Mr. Fangtooth just grunted.

Kiki tried, “Mr. Fangtooth, what was the scariest thing that ever happened to you?”

Mr. Fangtooth looked right at Kiki and snapped, “Working at Trident Academy.”

“Gee, that wasn’t very nice,” Echo said as the girls swam back to their table. “Why is he always such a grump?”

Kiki tied back her long, straight black hair with a bow and grinned. “I have a plan,” she said, and whispered the idea to her friends.

Echo smiled. “That sounds great. Watch this.”

Echo glided over to the service window of the lunchroom, followed by her friends. Mr. Fangtooth frowned at the mergirls. “Mr. Fangtooth,” Echo said. “What kind of hair does the ocean have?”

Mr. Fangtooth grunted again.

Echo giggled. “Wavy. Like ocean waves,” she said. “Wavy hair, like mine.”

Kiki laughed, but Mr. Fangtooth didn’t crack even the tiniest smile. “Mr. Fangtooth,” Kiki said. “Why are fish so smart?”

When Mr. Fangtooth didn’t answer, Kiki gave the punch line: “Fish are smart because they live in schools!”

Shelly couldn’t believe it. Mr. Fangtooth didn’t look up from scraping ribbon worms off trays. So Shelly tried the joke she’d heard a few days ago at Shell Wars practice. “Mr. Fangtooth, which fish is the most famous?”

Mr. Fangtooth put a big sign that said CLOSED! in front of the cafeteria window and swam away. “Well, that was rude,” Echo said.

Kiki nodded. “I wonder what made him such a meanie.”

“Tell us the answer,” Echo said to Shelly.

Shelly shook her head. “I don’t know what happened to him.”

Echo put her right hand on her hip. “No, silly. I mean which fish is the most famous?”

“Oh, that,” Shelly said with a giggle. “It’s the starfish, of course.”

Rocky soared over beside Shelly and announced in a loud voice, “I guess Princess Shelly is the most famous fish in our school.”

A group of third graders gathered around Shelly, led by Pearl.

“As a princess expert, I know that Shelly won’t be at Trident Academy for long. She’ll be moving to Neptune’s Castle to begin her royal duties,” Pearl said with an air of authority.

“Is that really true?” Pearl’s friend Wanda Slug asked.