The muskellunge, often shortened to muskie, musky or lunge, is a species of large freshwater predatory fish native to North America. It is the largest member of the pike family, Esocidae.
Muskellunge closely resemble other esocids such as the northern pike and American pickerel in both appearance and behavior. Like the northern pike and other aggressive pikes, the body plan is typical of ambush predators with an elongated body, flat head, and dorsal, pelvic, and anal fins set far back on the body. Muskellunge are typically 28–48 in (71–122 cm) long and weigh 15–36 lb (6.8–16.3 kg), though some have reached up to 6 ft (1.8 m) and almost 70 lb (32 kg).