The Gastrointestinal Tract of Fish. Immune Defences of Teleost Fish. Gastrointestinal Pathogenesis in Aquatic Animals. The Gut Microbiota of Fish. Methodological Approaches Used to Assess Fist Gastrointestinal Communities. Indegenous Lactic Acid Bacteria in Fish and Crustaceans. Probiotics and Prebiotics: Concepts, Definitions and History. Probiotic Modulation of the Gut Microbiota of Fish. Probiotic Applications in Cold Water Firs Species. Probiotic Applications in Temperate and Warm Water Fish Species. Probiotic Applications in Crustaceans. Can Probiotics Affect Reproductive Processes of Aquatic Animals?. Issues with Industrial Probiotic Scale-up. Prebiotics in Finfish: An Update. Prebiotic Applications in Shellfish. Live Feeds: Microbial Assemblages, Probiotics and Prebiotics. Index.