Blue pike, also known as the blue walleye, was a freshwater fish that once flourished in the Great Lakes but is now extinct. Synonyms for blue pike include Sander vitreus glaucus, Lake Erie blue pike, Great Lakes blue pike, and Stizostedion vitreum glaucum. These names highlight the fish's blue-gray coloring, which distinguished it from other walleye species. The blue pike was popular among anglers and a vital part of the Great Lakes ecosystem that played a role in controlling the population of invasive species. Unfortunately, the overfishing and habitat destruction of the blue pike led to its decline, and it was last seen in the wild in the 1960s.