Here's a handy guide that does what Dorling Kindersley's Eyewitness Handbooks do best: use pictures to give readers the information they want and need. In glorious full color, 500 marine and freshwater fish are pictured clearly and large enough to make this an identification manual that fish keepers won't want to be without. The fish are grouped into four general categories (tropical freshwater, cold-water freshwater, tropical marine, cold-water marine), then by family and species. Accompanying each clearly labeled photograph are brief remarks about habitat, behavior, and coloration; a small distribution map; and horizontal bar graphs supplying at-a-glance information on diet, temperament, and size. Mills doesn't provide enough for those setting up a tank for the first time, but the tips with which he leads off his text will start novices in the right direction.