A breathtaking insight into underwater life, this Encyclopedia offers unrivalled coverage of the fish and aquatic invertebrates that inhabit our rivers, lakes, and oceans. It describes in detail the anatomy, behaviour, habitat, breeding, and conservation status of species: from microscopic, single-celled organisms swept along by water currents to gigantic powerhouses of the deep. Fascinating feature articles examine some of the strangest and most interesting aspects of these species in more depth, such as the origins of coral reefs; the cycle of the salmon; and how fish produce and use artificial illumination.