Order Beloniformes
Suborder Belonoidei
The vast majority of representatives of the order are marine fishes, predominantly warm-water inhabitants. They live both in the open ocean and in shallow coastal areas of seas, and even in freshwater bodies. They mostly keep to the surface layers of water, and many of them, escaping from predators or pursuing prey, make leaps above the surface. Representatives of the order show a positive reaction to light. They feed on zooplankton and small fish. Freshwater species have evolved live-bearing.
The body of needlefishes is elongated, covered with small or medium-sized scales, and their powerful, elongated jaws equipped with sharp canine-like teeth clearly distinguish them from related families. The lateral line runs along the lower edge of the body. The dorsal and anal fins are located in the posterior part of the body, opposite each other, and the pelvic fins are placed on the belly. Their fins lack spiny rays. An interesting feature is that their bones are colored bright green by a bile pigment. The order is divided into two suborders: Scombresocoidei with two families (sauries and needlefishes), and Exocoetoidei with families flying fishes and halfbeaks.
It is preferable to keep needlefishes in a low aquarium, not more than 40 cm high, elongated in length. Needlefishes usually swim using undulating body bends, but are also capable of sudden, high-speed dashes. It is desirable that the back and side walls of the aquarium are densely planted with vegetation for cushioning, as when frightened, the fish can break their elongated jaws against the aquarium glass. When frightened or chasing prey (all needlefishes are predators feeding mainly on fish), they jump out of the water, making large leaps. A tightly fitted cover glass is mandatory.
Family Belonidae
The family includes fishes inhabiting mainly marine, less often brackish and fresh waters, mostly within tropical and subtropical zones. Needlefishes have a long and thin body covered with very small scales, and their powerful, elongated jaws equipped with sharp canine-like teeth clearly distinguish them from related families — halfbeaks, flying fishes, and sauries. For aquarists, Potamorrhaphis, Strongyllura, and Xenentodon are of interest.
Predators, sometimes small fishes from the needlefish family appear for sale, which must be handled with extreme caution! Freshwater needlefishes do not exceed 90 cm in size. They should be kept alone, without neighbors. They are colored predominantly in silvery-olive or bluish-gray tones. Males are brighter, slenderer, and smaller than females.
It is advisable to keep the fish in a large, elongated species aquarium, densely planted with plants and tightly covered on top with a cover glass (needlefishes are excellent jumpers). They usually swim using undulating body bends, but are also capable of sudden, high-speed dashes. When frightened or chasing prey (all needlefishes are predators feeding mainly on fish), they jump out of the water, making large leaps. Active aeration, filtration, and water changes are mandatory.
They feed mainly on small fish and tadpoles. With a prolonged absence of live fish in the diet, needlefishes develop dystrophy, the external manifestations of which are swelling of the gill region, poor food digestion, and emaciation. They mature at 12–15 months. For successful breeding, it is necessary to have a school of fish consisting of 2–3 males and 6–7 females. Lifespan in an aquarium is 3–4 years. dH 5–14°; pH 7–7.5; T 23–26°C, salinity 1–5%.
Genus Potamorrhaphis.
— Needle pikes — Potamorrhaphis eigenmanni [Miranda Ribeiro, 1915]. South America, Peru, Paraguay, upper reaches of the Madeira River and its tributaries (Beni, Mamoré, Guaporé) and the basin of the Paraguay and Paraná rivers. 20 cm. Differs in particularly beautiful coloration. Over the black longitudinal stripe, a narrower red stripe is visible. They need large aquariums. The fish are very jumpy, so an aquarium lid is mandatory.
These are very timid creatures that, when frightened, panic and can easily injure themselves. Often, these pikes show damage to the tips of their “beak”, which leads to inflammation and fungal infections. Sometimes beak fractures are even possible. With proper care, they live in aquariums for a long time. They accept only feeder fish and large insect larvae, refusing non-living food.
— Potamorrhaphis — Potamorrhaphis guianensis [Jardine, 1843]. Synonym: Belone guianensis, scolopacina, taeniata, Pseudotylosurus microps. Water bodies of Guyana to the border with Paraguay, Amazon and Orinoco river basins. 29 cm. The main coloration is translucent silvery-gray (brownish above, greenish below). A dark brown sparkly stripe runs along the body of the fish, which, depending on its mood, appears and disappears.
A fairly spacious aquarium with a large bottom area, densely planted with plants and covered on top with glass. Very timid and often, when frightened or when the light is suddenly turned on, they injure themselves against the glass. They lead a crepuscular and nocturnal lifestyle, staying near the water surface. To facilitate the acclimatization of the fish, the aquarium should be dimly lit. There should always be some floating plants on the surface where the fish can hide. Aeration, filtration, and water changes are mandatory. Initially, they accept almost exclusively live food, after some time they can get used to slowly sinking frozen products. pH around 7; dH up to 8°; T 24–28°C.
Genus Xenentodon.
— Silver Asian needlefish — Xenentodon cancila [Hamilton, 1822]. Synonym: Belone cancila, graii, Esox cancila, hindostanicus, indica, Xenentodon canciloides. (English: Freshwater Gar Fish, Freshwater Needle Fish, Needle Nose Gar, Silver Needlefish). India, Bangladesh, Myanmar, Sri Lanka, Malacca Peninsula, Indonesia, Thailand. Male up to 25, female up to 30 cm.
Due to their slender, needle-like body shape, the fish do not appear bulky even at maximum sizes. Almost a quarter of the fish’s total length is occupied by a tweezers-like mouth with small sharp teeth. Sharp teeth are used to catch prey, and then, skillfully turning the prey, it swallows it. The ends of the dorsal and anal fins coincide with the beginning of the caudal fin. There are no pelvic fins. The rear edge of the caudal fin is convex.
Silvery-gray with a greenish tint. The back is olive-brownish, the belly is silvery-greenish. A black sparkly stripe runs along the body of the fish, which, depending on its mood, appears and disappears. Adult fish have small spots on the flanks between the dorsal and anal fins. Fins are colorless. The male has a black edge on the dorsal and anal fins. During spawning, males turn a bluish-steel color, the stripes disappear, the lower jaw turns pink, and a red, slightly protruding stroke in a dark halo appears on the nape.
Aquarium from 200 liters, there should be 15 cm to the cover glass. It occupies the upper water layers, so floating plants with long roots are placed on the surface. In the aquarium, dense vegetation along the glass and driftwood are used to create shelters. The fish have very nervous behavior, react to sudden changes in lighting, movements, and dart away like lightning, hitting the glass, decorations, or jumping out.
A timid, schooling fish that should be combined with large fish that they cannot swallow, swimming near the bottom. In conflict situations, skirmishes are observed. In this case, the fish bend like the letter S, gills swell, and then swift strikes follow. Bruised scales and abrasions are evidence of such duels. Aeration, filtration, and water changes are mandatory.
They prefer slightly brackish water. The current from the filter should not create a strong flow on the water surface. A schooling predator, feeding mainly on small fish, live shrimp, crickets, and even tadpoles; it is completely indifferent to high-bodied fish. With a prolonged absence of live fish in the diet, needlefishes develop dystrophy, the external manifestations of which are swelling of the gill region, poor food digestion, and emaciation.
These fish can inflict unpleasant and painful bites; do not lower or place your hand on the edge of the aquarium. They mature at 12–15 months. The female hangs sticky eggs on plants in clusters of 2–5 very large transparent eggs. After a month, the fry reach a length of 4 cm. Lifespan in the aquarium is about 8 years. dH around 10°; pH 7–7.5; T 25–28°C, salinity 2–10%.
Identification: Silver needlefish — Xenentodon cancila.
Hemirhamphodon chrysopunctatus, pogonognathus, phaiosoma, tengah.
Sturgeons: Genus Acipenser, Genus Pseudoscaphirhynchus, Genus Scaphirhynchus. 
