Helen Scales is a marine biologist, diver, and surfer, and is no stranger to writing good books. I have previously read Poseidon’s Steed: The Story of Seahorses, from Myth to Reality from her hand. The book after that, Spirals in Time: The Secret Life and Curious Afterlife of Seashells, received critical praise in the press and was shortlisted for the Royal Society of Biology book prize. Here, Scales turns her attention to fish. Is this another page-turner waiting to be recognised?