This book provides comprehensive and research-focused information regarding novel developments in the field of fish biology. It provides the readers with a comprehensive study on fish biology. Recent advancements on cellular and molecular biology and ecology have led to the collection of advanced scientific knowledge in this area. Prominent research works from across the globe have been compiled in this book to provide a useful source of reference for researchers, teachers as well as students of advanced biological sciences. This book provides the readers with a basic description of the complex biology of immune response. In-depth descriptions have also been included for the intensive understanding of cytokine regulation in teleost immune system. Important details about the environmental stressors on the responses of fish from molecular to population level have also been provided. The book also discusses topics like the roles of the atrium and the ventricular system in teleost species and the tracer methodologies used for measurements of carbohydrate metabolism. It talks about the variables responsible for the feeding action of a predacious freshwater fish species.