Mackerel are a group of slender, streamlined, and swift-moving fish found in temperate and tropical seas worldwide. They are known for their distinctive appearance, often featuring silvery skin with dark, wavy stripes on their upper bodies. Mackerel are also characterized by their forked tails, two well-separated dorsal fins, and rows of small finlets behind the dorsal and anal fins. They are a good source of omega-3 fatty acids and are known for their versatility in cooking.