It has an elongated body, up to 2.5 m long, a spearlike snout, and a long rigid dorsal fin, which extends forwards to form a crest. Marlins are fast swimmers, occurring in all seas and hunting small fish.

The larger species include the blue marlin, Makaira nigricans, which grows to 4.6 m (14.6 feet) long and around 450 kg (992 pounds). They are popular sporting fishes in certain tropical areas and are also commercially important as a food fish. It is also the primary charectar in Ernest Hemmingway's "The old man and the sea" see also: Florida Marlins (baseball team)