Fish are aquatic animals that live in both freshwater and saltwater environments and are an essential part of the global ecosystem and human diet. They come in a wide variety of species, ranging from small, colorful tropical fish to large, commercially valuable types like tuna, salmon, and cod. Fish are a rich source of high-quality protein, omega-3 fatty acids, vitamins such as D and B2, and essential minerals like calcium, phosphorus, iron, zinc, iodine, magnesium, and potassium. These nutrients contribute to heart health, brain development, and overall well-being. Fish can be prepared in numerous ways—grilled, fried, baked, steamed, or raw in dishes like sushi—making them a versatile food choice in many cultures. In addition to their dietary importance, fish also support livelihoods through fishing and aquaculture industries around the world.