By far the best fish book I can recommend is "Confessions of a Fish Doctor" by Scott Brodie. You'd have to find it on-line as it is out of print, but a great book. Written by a guy in New York who worked in a fish store maybe 30 years ago, he will show you how fish have different personalities and how to make tanks come alive. More of a memoir, but lots of good solid advice on fish keeping. Really, really, really good.
Peter Scott's "The Natural Aquarium" is a great read and a lavishly illustrated introduction to the concept of biotope tanks.
And last, I cannot remember the title, but the book is written by Stephen Reebs (just came out last year) about how fish live, how they sense things underwater, etc. A good book about fish biology for a non-science person.
Val