Pounder, Sibéal. Bad mermaids #2

"Mermaids Beattie, Mimi and Zelda, and Steve the talking seahorse, are trapped aboard the spooky ship the Merry Mary, heading for the presumed-mythical Crocodile Kingdom - a vast, crocodile-filled metropolis where nothing is quite as it seems. It's time to swim on down to the bright green lights and explore the oldest and grandest mermaid kingdom of them all! Just don't let any mermaid know you're not from there. Or else."--Publisher description