This is the book you need.  Used as the textbook for the AKCA Koi Health Advisors training class.

This book contains comprehensive and extensive information regarding every aspect of Koi health. With detailed information on husbandry, prevention, treatment and a multitude of other topics, all illustrated with high quality color photos, this is the must have Koi book for every serious Koi keeper.

Perfect Bound soft cover, 200 pages, 400+ color photographs, charts, formulary, glossary, fully indexed.