Fish physiology is the study of how fish bodies function and adapt to their aquatic environments. Fish have specialized organs, such as gills, which allow them to extract oxygen from water. Their bodies are streamlined for efficient swimming, and they possess a swim bladder that helps them maintain buoyancy. Additionally, fish have unique circulatory systems that pump blood through their gills and body. Their sensory systems, including lateral lines, help them detect movement and vibrations in the water. Understanding fish physiology is essential for fields like marine biology and aquaculture, as it informs conservation and breeding practices.