An underwater exploration that overturns myths about fishes and reveals their complex lives, from tool use to social behavior There are more than thirty thousand species of fish--more than all mammals, birds, reptiles, and amphibians combined. But for all their breathtaking diversity and beauty, we rarely consider how fish think, feel, and behave. In What a Fish Knows, the ethologist Jonathan Balcombe takes us under the sea and to the other side of...