Bony fish, or Osteichthyes, are a diverse group of fish characterized by a skeleton made primarily of bone rather than cartilage. They are the largest class of vertebrates, with over 30,000 species, including familiar types like salmon, trout, and tuna. Bony fish typically have a swim bladder, which helps them maintain buoyancy in water. These fish are found in various aquatic environments, from freshwater lakes to the open ocean. Bony fish possess scales covering their bodies and gills for breathing underwater. They play essential roles in ecosystems and are important for human consumption and recreational fishing.