Esox lucius, commonly known as the northern pike, is a species of freshwater fish found in North America, Europe, and Asia. It typically inhabits lakes, rivers, and marshes, preferring areas with abundant vegetation. The northern pike is known for its elongated body, sharp teeth, and distinctive greenish coloration with lighter spots. This predatory fish can grow quite large, often reaching lengths of 20 to 30 inches, although some individuals can exceed 50 inches. Esox lucius is an important species for both recreational and commercial fishing, valued for its fighting ability and taste.