The blue runner has an elongated, slightly compressed body with characteristic olive to dark blue highlights on the upper back and silvery gray flanks. It has a black spot, more or less visible, near the upper edge of the gill cover.

Blue runners typically reach an average length of 16 inches, while some individuals can grow up to 27.5 inches long.

Juveniles often display seven dark vertical bars along their flanks.

Blue runners inhabit the tropical and temperate waters of the Atlantic ocean, from the coasts of Canada in the north to Brazil in the south, including the Gulf of Mexico and Caribbean islands in the western Atlantic, as well as along the west African coasts from Senegal to Angola in the eastern Atlantic, and also the Mediterranean sea.

The blue runner is a pelagic and schooling species, often seen in dense schools near the coast as well as in deeper waters, sometimes forming large groups of several thousand individuals.

The blue runner is a carnivorous and opportunistic species, feeding mainly on smaller fish, crustaceans such as shrimp and crabs, and other invertebrates.

Spawning occurs offshore throughout the year, with a peak in summer in certain regions like the Gulf of Mexico. During reproduction, females release their eggs into open water, which drift with the currents before hatching. The floating larvae then gradually migrate toward coastal areas as they grow.

The blue runner is listed as many other marine species within The IUCN Red List of threatened species. The blue runner appears in the IUCN Red List since 2010 within the category Least Concern !