A
marlin is a fish from the family Istiophoridae (includes about 10 species). It has 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, marlins are fast swimmers, reaching speeds of about .