Esocidae is a family of ray-finned fish in the order Salmoniformes, which contains pike, pickerel, and mudminnows.

Species in the genus Esox can be found in Eurasia and North America, while Dallia has a more restricted range in Alaska and eastern Siberia.

Estesesox fossils have been described from the Lance, Hell Creek, Oldman, Foremost, and Milk River Formations.

[3][4] While the Olympic mudminnow is aggressively territorial to fish of the same size during the spawning season, it will generally leave its fry alone.

Due to the fragmentary nature of Oldmanesox and Estesesox, little information on the exact relationships between the two genera and the rest of the species in the family has been published.