Contents include: Causes, development and prevention of fish diseases; General diagnosis; Prophylaxis and therapy of fish diseases; Status of fish diseases and mortalities therefrom. Organisation for controlling diseases in the German Democratic Republic; Diseases caused by pathogenes (Virusses and bacterioses, Algoses, Mycoses, Protozoiases, Helminthiases, Diseases caused by Crustacean parasites); and Diseases not caused by pathogenes (Diseases from environmental stresses, diseases due to nutritional imbalance, other diseases not caused by pathogens).