Order Beloniformes
Family Hemiramphidae
Subfamily Zenarchopterinae
Genus Dermogenys
In Dermogenys, the fixed lower jaw is twice as long as the upper jaw, which is movable and allows fish to catch food from the water surface. These are schooling fish, swimming near the water surface. Predatory, they feed primarily on flying insects that have fallen onto the surface. Males can be aggressive toward each other. It is best to keep adult Dermogenys separately to fully reveal their species characteristics.
A hierarchy is established in a school of Dermogenys among both males and females. This is especially clear in males when settling disputes and in females during feeding. The right to propagate goes to the strongest. Keep them in reasonably sized, well-planted aquariums.
Dermogenys are avid adherents of the surface layers; they seem glued to the surface. They do not even have time to dive for food. However, pursued individuals are quite capable of staying in the middle and lower layers. Nevertheless, even when fleeing from danger, they prefer not to dive, but to jump out of the water.
Foods must be floating or at least stay on the surface for some time. Before throwing bloodworms into the water, they need to be dried out slightly. This applies equally to live and frozen foods. The larger the surface area of the aquarium, the better, and at least half of the water surface should be free of vegetation, as the fish feel most comfortable when their napes are “glued” to the water-air boundary.
They are practically immune to short-term temperature fluctuations, but should be kept at a temperature of 23-27°C. In natural conditions, these species inhabit mainly brackish waters; nevertheless, in the aquarium, they feel great in completely fresh water as well.
Livebearing. Fry at birth are 7-11 mm long, and their number, depending on the age and body structure of the female, ranges from 8 to 25 per brood. Aquariums contain wrestling, Philippine, long-snouted, Sumatran, and other Dermogenys with similar maintenance conditions.
Also kept: — Dermogenys montana (Brembach, 1982) — Mountain halfbeak. Synonym: Dermogenys montanus. Indonesia, Sulawesi Island, Bantimurung. Male 5, female 9 cm. Female is silver with a brown back, orange-yellow fins and snout. The male has a yellow tail with an orange border.
— Freshwater Halfbeak, Gar Halfbeak, Malayan Halfbeak, Silver Halfbeak, Wrestling Halfbeak — Dermogenys pusilla [Kuhl & Hasselt, 1823]. Synonyms: Dermogenys burmanicus, pusillus, siamensis. Indo-Malayan archipelago, Thailand, Singapore, Java, Greater Sunda Islands, fresh and brackish waters. Male 5-6 cm, female up to 7 cm.
The body is thin and elongated, compressed laterally. The head is pointed, elongated. Unpaired fins are shifted backward, rounded. In body structure, the fish resembles a pike, where everything is adapted for a lightning-fast forward rush. The sharply elongated lower jaw is especially striking. The upper jaw is short and moves together with the skull.
The body is completely transparent, allowing the gills, spine, and internal organs to be seen. For a sharp dash to the surface, the fish has rounded anal and dorsal fins shifted far back and located opposite each other. The pectoral fins are disproportionately large, raised upward like butterflies. There are no bright colors in the coloration; the body is silvery-gray with green or blue shades, the fins are yellowish.
Coloration depends on the place of origin: either yellow-brown with a metallic sheen, or silvery with a bluish tint, with the finest dark reticulated pattern. The back is light brown, turning into silvery-gray towards the belly. The belly is white or light yellow.
Females have a slight reddish-brownish tint in the belly area. The bases of the dorsal and anal fins are red, and in males this field is larger and brighter, but in females, the dark border surrounding it is more pronounced. The tips of the ventral fins, which are shifted far back toward the tail, are black.
The lower jaw has black and often red longitudinal lines. In males, the lower jaw and dorsal fin are colored reddish-orange, the anal fin becomes stepped and acquires a reddish coloration. In females, the fins are transparent with a yellowish tint, and the anal fin is flag-shaped.
Males are leaner, smaller, and more brightly colored. They have a longer lower jaw than the Celebes halfbeak, and it is the most vulnerable place during transportation. Injury to it often leads to infection and death, so make sure you purchase a specimen with an undamaged lower jaw.
In nature, it forms 4 subspecies: — D. pusillus burmanicus – Burmese; — D. pusillus orientalis – Eastern; — D. pusillus siamensis – Thai; — D. pusillus sumatranus – Sumatran.
They can be kept in as large a community aquarium as possible with fish of a similar size (just not upper-layer fish), but preferably in a species aquarium where Dermogenys can fully reveal themselves. The aquarium should be covered on top (the fish are good jumpers), with thickets of tall and floating plants with thread-like roots pointing downwards, but also with sufficient swimming space.
Moderate lighting. They feed from the water surface on insects that have fallen onto it. For this, the fish has a fixed lower jaw extended far forward. The movable upper jaw allows them to capture and hold prey in the mouth.
They occupy exclusively the upper water layer and never descend below a depth of 5-10 cm. Even when hungry, they rarely descend to the middle and lower water layers. If this happens, it is a sign of fish malaise. Only in one case can a female Dermogenys descend to the middle layers of the body of water — during spawning.
Males are so aggressive among themselves that, along with the Siamese fighting fish (Betta), they are used in fights. Despite the fact that these fish fight for territory and drive each other away, they should be kept in a school of 6-10 fish. It is necessary to keep 2-3 females per 1 male.
In the aquarium, females and males initially compete with each other, but without serious injuries. Then a hierarchy is established, and the weaker submits to the stronger. Halfbeaks simply pay no attention to neighbors of other genera, including much smaller ones. They can snatch food from under their noses, push them away, or scare them with a wide-open mouth — nothing more.
Up to a third of the water volume should be replaced with fresh water weekly. A small addition of salt is desirable. Aeration and filtration are mandatory. They take any live food — small crustaceans, tubifex, mosquito larvae, eagerly rushing to floating artificial foods.
Livebearing fish, maturing at 5-6 months. Fertilization of females occurs via the male’s andropodium, which is formed by the first rays of his anal fin. As a rule, a male is near the female, jealously guarding her from other males.
Females are fertilized by males in the general aquarium and carry offspring for 60 days. When the female’s anal opening swells and her belly becomes full, she must be placed in a small aquarium (5-10 liters with a water level of 6-8 cm) densely planted with plants.
The female produces fully formed fry, which must be separated immediately, as they can be eaten, especially by the female. Growth occurs very quickly, so they must immediately be provided with the same food as the adults. After 4-6 weeks, she brings fry again. They live up to 5 years. pH 6.8-8.0; dH 10-15°; T 26-28°C.
Identification: Dwarf halfbeak — Dermogenys pusilla.
Nomorhamphus celebensis, Nomorhamphus liemi.
Hemirhamphodon chrysopunctatus, pogonognathus, phaiosoma, tengah. 
