Fish are critically important to the welfare of this planet and its occupants, the health of both wild and captive fish populations paramount to our survival. This book presents the gross pathology of the most commonly encountered diseases and syndromes of fish in an organ system-based approach. It provides an overview of the diseases and disorders of tropical, ornamental, bait and food fish from freshwater, brackish and marine environments. Readers will gain a broader understanding of the basic biology of infectious and non-infectious diseases in fish, as well as novel diagnostic techniques and innovative disease control methods.