Swordfish (Xiphias gladius), are large, highly migratory, predatory fish characterized by a long, sword-like pointed bill. This makes them superficially similar to other billfish such as marlin, but upon examination, their physiology is quite different and they are members of different families. They are a popular sport fish of the billfish category, though elusive. Females are larger than males, and Pacific swordfish reach a greater size than northwest Atlantic and Mediterranean swordfish. They reach maturity at 4–5 years of age and the maximum age is believed to be at least 9 years. The oldest swordfish found in a recent study were a 16-year-old female and 12-year-old male. Swordfish are elongated, round-bodied, and lose all teeth and scales by adulthood. Swordfish have special organs next to their eyes to heat their eyes and brains. The heating of the eyes greatly improves their vision, and consequently improves their ability to catch prey. Of the 25 000+ fish species, only 22 are known to have a mechanism to conserve heat. These include the swordfish, marlin, tuna, and some sharks. These fish are found widely in tropical and temperate parts of the Atlantic, Pacific, and Indian Oceans, and can typically be found from near the surface to a depth of 1,800 ft, and exceptionally up to depths of 7,330 feet. They commonly reach 9.8 ft in length, and the maximum reported is 14.9 ft in length and 1,430 lb in weight. The International Game Fish Association's all-tackle angling record for a swordfish was a 1,182 lb specimen taken off Chile in 1953. -Copy and pasted from Wikipedia Courtesy of The Bellisseria Oceanographic Institute