Fish are aquatic animals that have gills, fins, and a streamlined body, allowing them to thrive in water. They are an essential part of the ecosystem, serving as both predators and prey. With over 30,000 species, fish can be found in a variety of habitats, from freshwater rivers to the depths of the ocean. Fish play a crucial role in human culture and economy, providing food and recreation. Popular species like salmon and tuna are not only enjoyed in cuisines worldwide but also contribute significantly to commercial fishing industries. Understanding fish is vital for conservation efforts and maintaining biodiversity.