If you want to start getting into a more technical (and accurate) ID guide, I would recommend starting with Freshwater fishes of North America in the Peterson Field guide series. You'll probably want to progress further from that book but it's a great start and very inexpensive. It provides much more detailed descriptions (including scale, ray and other counts) and practical key features to distinguish similar fishes. This book has it's shortcomings but hey...it's a small inexpensive book attempting to cover every single NA freshwater fish. That is one heck of a task.
Jim,
I guess you lost my email?? I wasn't trying to make you post in public, but I'm glad the fish is well and looking good.