Esociformes

Esociformes is an order of ray-finned fishes that comprises two living families: Esocidae (pikes) and Umbridae (mud minnows). They form a relatively small, cold- or temperate-water lineage of freshwater fishes and are considered part of the superorder Protacanthopterygii within Teleostei. Fossil evidence shows that the group has a long evolutionary history, with relatives dating back to ancient freshwater environments.

Members of Esociformes are generally elongated, predatory fishes. Pikes (Esocidae) typically have sharp, pointed snouts and prominent teeth, while mud minnows (Umbridae) are usually smaller and more compact. A common morphological feature is fins positioned toward the rear of the body, which, along with their streamlined shape, supports their ambush-predator lifestyle in aquatic habitats ranging from rivers and lakes to wetlands.

Ecology and life history vary somewhat between the two families but share a preference for cooler, freshwater environments. Pikes are well known as active predators that feed on other fishes and invertebrates. Mud minnows tend to occupy slower-moving waters and often exhibit more generalist tendencies in habitat use. Reproduction in Esociformes is oviparous, with spawning in spring or early summer; eggs are usually laid in vegetation or on submerged substrates, where they adhere and develop into larvae.

Distribution and conservation status also differ by group. Esocidae pikes are widespread across Eurasia and North America, while Umbridae mud minnows occur in parts of North America and Asia. As predators and potential top- or mesopredators in freshwater ecosystems, Esociformes play important ecological roles; some species are valued as game fish, while others face pressures from habitat loss, water pollution, and invasive species.