A marlin, family Istiophoridae, is a fish with an elongated body, a spear-like snout or bill, and a long rigid dorsal fin, which extends forward to form a crest. Its common name is thought to derive from its resemblance to a sailor's marlinspike. Even more so than their close relatives, the scombrids, marlin are incredibly fast swimmers, reaching speeds of about 110 kilometres per hour (68 mph).
The larger species include the Atlantic blue marlin, Makaira nigricans, which can reach 5 m (16.4 ft) in length and 818 kg (1,800 lb) in weight and the black marlin, Makaira indica, which can reach in excess of 5 m (16.4 ft) in length and 670 kg (1,500 lb) in weight. They are popular sporting fish in tropical areas.
Marlin are rarely table fare, appearing mostly in fine restaurants. Most modern sport fishermen release marlin after unhooking.
Very large marlin, which may set a record, are taken and weighed on shore. Records are most often recorded in the IGFA World Record Game Fish books. The current record has stood for some 20 years.