Needlefish (Belonidae) is a family of fishes of the Sarganiformes (Beloniformes). It includes 12 genera, more than 30 species. The body is elongated, covered with scales. Jaws ullinated in the form of a beak, with fine teeth. Marine, less often brackish-water fish tropical, subtropical, sometimes temperate areas of the World Oxan. Freshwater species are found only in the tropics. In Russia live 2 species of common sargan (Belone belone) - predator, up to 90 cm long and weighing up to 1 kg, inhabiting the Baltic, Black, rarely in the White Sea, and Far Eastern sargan (Strongylura anastomella) up to 90 cm long, inhabiting the coastal areas of the southern part of Primorye. Needlefish are of minor commercial importance.

Body elongate, compressed from sides, or rounded or square in cross-section; covered with fine cycloid, easily falling scales. The jaws are long, of equal length, forming a characteristic "beak". Metamorphosis of jaws is characteristic. In larvae after hatching, the length of the upper and lower jaws are the same. As the fish grows, initially begins to lengthen the lower jaw (the so-called "half-reed stage"). Then lengthens the upper jaw, and eventually the jaws acquire the same length. Both jaws have numerous needle-shaped sharp teeth. In two freshwater species of the genus Belonion, the upper jaw is short. Nostrils are located in the fossa in front of the eyes. Dorsal and anal fins are moved far back to the caudal peduncle. There are no stiff rays in the fins. The dorsal fin has 11-26 soft rays (up to 43 in some species). The anal fin has 12-39 soft rays. There are no additional fins behind the dorsal and anal fins. Pectoral fins are short, with 5-15 soft rays. The pelvic fins with 6 soft rays are located on the belly. The caudal fin is notched or truncated. The lateral line runs low on the body, starting at the beginning of the pectoral fins; it usually has 130-350 scales. The vertebrae are 52-97, of which 33-65 are trunk vertebrae and 19-41 caudal vertebrae.

The body coloration of most representatives of the family is due to their pelagic lifestyle near the water surface. The upper body is greenish or bluish, while the lower body and belly are silvery-white. There are usually pale or dark blue stripes along the sides of the body. The tip of the lower jaw is sometimes red or orange. The color of bones in representatives of the family is from light to dark green, due to the increased content of biliverdin.

Representatives of four genera (Belonion, Potamorrhaphis, Pseudotylosurus and Xenentodon) are distributed in freshwater bodies of South America. In the genus Strongylura, the most representative in the number of species and diversity of life style, most species are distributed in marine and brackish waters of the Atlantic, Indian and Pacific Oceans; representatives of three species inhabit freshwater bodies of South and Central America, Asia, Oceania and Australia. Representatives of the remaining genera are marine fishes inhabiting both coastal and open waters of seas and oceans.

Feeding mainly on small fish, the diet also includes crustaceans and small cephalopods.

Most sargans move with great speed and are capable of jumping out of the water. This makes them a serious danger to humans (fishermen, divers, snorkelers, divers, surfers, kitesurfers, etc.). Penetrating wounds are inflicted by the beak of fish. Fish can also bite humans. Numerous cases of injuries to the head, torso, legs have been reported; fatalities have been recorded.

They belong to the number of edible fish, although in some countries there is a certain prejudice to them due to the strange green coloration of their bones. Most sargans are harvested only for local fresh consumption, and only a few are targeted by special fisheries.