Threadfins are silvery grey perciform marine fish of the family Polynemidae. Found in tropical to subtropical waters throughout the world, the threadfin family contains nine genera and 33 species. An unrelated species sometimes known by the name threadfin, Alectis indicus, is properly the Indian threadfish (family Carangidae).

Ranging in length from 20 centimeters (7.9 in) in the black-finned threadfin (Polydactylus nigripinnis) to 200 centimeters (79 in) in fourfinger threadfins (Eleutheronema tetradactylum) and giant African threadfins (Polydactylus quadrifilis), threadfins are both important to commercial fisheries as a food fish, and popular among anglers. Their habit of forming large schools makes the threadfins a reliable and economic catch.

Their bodies are elongate and fusiform, with spinous and soft dorsal fins widely separate. Their tail fins are large and deeply forked; indicating speed and agility. The mouth is large and inferior; a blunt snout projects far ahead. The jaws and palate possess bands of villiform (fibrous) teeth. Their most distinguishing feature is their pectoral fins: they are composed of two distinct sections, the lower of which consists of between 3-7 long, thread-like independent rays. In Polynemus species there may be up to 15 of these modified rays.

Johnny Mitchell, Jr. (born January 20, 1971 in Chicago, Illinois) is a former professional American football tight end in the National Football League for the New York Jets and Dallas Cowboys. He played college football at the University of Nebraska and was drafted in the first round (fifteenth overall) of the 1992 NFL Draft.

Mitchell graduated from Simeon Career Academy (then known as Simeon Vocational High School) in 1989.

He is currently serving as a studio analyst for British television channel Sky Sports on their live NFL coverage, and is the Offensive Line coach for the Merseyside Nighthawks.