The appropriately named Helen Scales has written a book about fishes that’s even better than What a Fish Knows or The Dragon Behind the Glass. Her book is mind-boggling because she advocates the belief that fish are intelligent–in their own way. At least one fish–the manta ray–has passed the mirror test. That is when an animal knows it is looking at itself when it gazes into a mirror. Human children, chimpanzees, elephants, dolphins, and Eurasian magpies have passed the mirror test. Some fish have good memories, like the goby. They live in pools on rocky shores and can memorize the location of all the rocks and pools in its surroundings at low tide so they can better escape predators. If they are removed from their habitat for a week and then are put back in the same habitat, they can remember the pool layout. Besides the intelligence of fish, Scales tells us about fish that glow, fish that are toxic, as well as noisy fish, extremely colorful fish (Why? Camouflage.), and fish that eat very strange things, like vegetarian piranhas. There’s hardly a page in this book that doesn’t have some fascinating fact on it. This book is one of the three best nonfiction books I read in 2018. The other two were The Feather Thief and The Rise and Fall of the Dinosaurs. This book is highly recommended.