Order Cyprinodontiformes
Superfamily Cyprinodontoidae
Family Nothobranchiidae
Continued…
Genus Nothobranchius. N.
— Nothobranchius rachovii [Ahl, 1926] — Rachov’s Nothobranch. Code: RAC. (Eng. Bluefin Notho, Rachov’s Nothobranch, Rainbow Nothobranch). This is one of the most beautiful fish not only among Nothobranchius, but also among all killifish. Distributed in the waters of East Africa, in areas adjacent to the Mozambique Channel. The southernmost population of N. rachovii was discovered in Kruger National Park. It differs from northern forms by less intense coloration, paler colors, and smaller, though more numerous, dots on the fins. Length up to 6 cm. One of the most beautiful aquarium fish.
Four forms differing in coloration are known. In the first form, the main color is blue with a turquoise tint; in the second, red with orange; in the third, green with a dark border on the scales; in the fourth, with blackish fins and a green-black reticulated body. The body coloration of males is dominated by one or two colors depending on the habitat: orange-red or blue with a turquoise tint, so one can also speak of red and blue lines. Individual populations have more red or blue components, especially on the unpaired fins with their speckled (orchid) pattern.
Differences are also observed in individual specimens of the same local variety. For example, in the blue form, the reticulated scale pattern looks redder against a blue background, and vice versa in the red form. However, all local forms are typified by rich orange-red throats and sickle-shaped marginal stripes on the caudal fins, adorned additionally with a narrow black border. Females, with their pale gray-brown coloration and transparent fins, look very modest. Compared to females of other Nothobranchius, they are much lighter and therefore easily distinguished (even at a very early age) from other species with which they might accidentally find themselves.
In males, the back is dark green, the flanks are bluish with reddish-golden, orange-yellow, and red spots and strokes. Depending on the lighting, this reflective blue color can become more saturated or lighter. In reflected light, blue areas shimmer blue, and yellow areas shimmer golden. The scales are bordered with orange-red, creating the impression, especially on the rear part of the body, of transverse red-orange bands around the body. The belly is golden-yellow. The dorsal, anal, and caudal fins are bluish with red spots and strokes, with the lower edge of the anal fin and the rear edge of the caudal fin ranging from golden-yellow to red. Pelvic fins are dark red, bluish at the base.
A small outer part of the caudal fin is shiny black, sharply contrasting with the orange band in front of it. Red to red-brown, sometimes even black dots are located on the dorsal, anal, and caudal fins and vary in number, size, and color. Females are dull brownish-yellow, without any noticeable pattern. The ventral side is silvery, above which a faint bluish sheen can be noticed. All fins are colorless and transparent.
Males from the Kruger National Park population are especially brilliantly colored, displaying a green-blue iridescent color on the tail surface and a shimmering greenish-golden color on the flanks. The iris of the eye is gold, and the throat and chest are suffused with crimson. Usually, there are series of irregular oblique crimson stripes on the flanks, and the pectoral fins are edged with white.
During the spawning period, the body of males becomes dark blue, almost black. On the caudal fin of adult males, there is a very distinct wide subterminal bright-red band, followed by a crescent-shaped marginal dark-blue band. The dorsal and anal fins also have blue marginal zones, and these fins are covered with irregularly shaped patches of dark blue or indigo color. Females of this population are more “adorned” compared to other populations, being more uniformly olive or yellowish-brown with a faint greenish sheen.
Males are sometimes aggressive towards their conspecifics; a certain hierarchy is established in their group, and it should not be disrupted by transferring males. This will only lead to aggressive fights. After the fish have lived in the aquarium for some time, each male claims his own territory, which he jealously defends against trespassing neighbors. Wild-caught males are generally more aggressive than tank-raised fish of the same species. The best way to combat aggression is to raise and keep them in groups of 5-6 males and 10-12 females. They will look wonderful in the lower tier of the aquarium among plants under strong lighting.
This species prefers a species-specific aquarium with a dark substrate and plenty of sunken driftwood. Such a dark to shaded environment significantly enhances color contrast. In a community aquarium, especially if introduced too young, they remain timid and will starve to death as other fish will not let them near the food. In aquarium practice, keeping them in medium-hard water with an approximately neutral pH has proven effective. Infestation with Oodinium, a true scourge of Nothobranchius, occurs much less frequently in such an environment. Furthermore, the pH of harder water is easier to stabilize since peat is usually used as a spawning substrate. Feed with live food. Treatment, or better yet disease prevention, should be done by adding 5 grams of salt per 10 liters of water. Breeding is uncomplicated. Lifespan is 5-7 months, depending on temperature and maintenance conditions. pH 6-7; dH up to 12°; T 18-22°C.
Identification: Nothobranchius rachovii.
— Nothobranchius rubroreticulatus [Blache & Miton, 1960] — Nothobranchius rubroreticulatus. Code: RUR. Lake Chad. 5 cm. Males feature a purple reticulated pattern all over the body against a light green main color with pearlescent shine; the mesh is formed by scales bordered in purple. The head is also purple with large shiny spots on the gill covers. The dorsal and anal fins are covered with irregular but numerous purple dots. At the base of these fins, individual dots merge to form a uniformly colored band in the middle part. This band is limited by a marginal black border running along the entire outer edge of the fin and a well-defined white strip.
The caudal fin is dark red for 2/3 at the base, followed by a transverse white band with a bluish sheen. Pelvic and pectoral fins are colorless. Pectoral fins are rounded or slightly triangular. In females, pectoral fins do not reach the base of the pelvic fins, whereas in males they reach the base or even slightly extend past it. The caudal fin is rounded in females and slightly triangular in males. Females lack any pattern. The main coloration is light yellowish-gray, slightly darker on the back, without patterns or dots. Fins are transparent, slightly uniformly yellowish.
— Nothobranchius symoensi [Wildekamp, 1978] — Nothobranchius symoensi. Code: SYM. Synonyms Nothobranchius brieni, sensu. Republic of the Congo, as well as the northeastern part of Zambia. 6 cm. Males have a stout build with a hump-like adipose structure on the anterior part of the back, which in older specimens can create a curved profile of the upper body. The origin of the dorsal fin is slightly ahead of or at the same level as the origin of the anal fin. Both dorsal and anal fins in folded condition reach the base of the caudal fin.
Males are distinguished by very beautiful coloration, characterized by a red-orange main color overlaid with light blue scales and randomly scattered carmine-red vertical or oblique stripes on the rear body. On the green-blue body areas, there are thin red-brown borders on the scales. The head is red-orange, gill covers are covered with blue speckles forming 2 irregular or backward-slanting red-brown stripes. The chin ranges from light red-orange to yellow.
Unpaired fins are richly colored and patterned. Numerous, sometimes elongated carmine-red speckles and strokes are randomly scattered over a light blue to green background. They also feature light blue to white edges. Pectoral fins are yellowish to light orange with a blue border. Females are not much smaller than males, light grayish to greenish, light brown with a silvery belly. They lack any distinct coloration, except for light blue shiny speckles at the level of the gill cover. There is also a similar sheen on the scales of the anterior body. All fins are transparent.
Males perform display attacks and short chases against each other, which occasionally result in serious injuries for lower-ranking males and smaller specimens. It is also recommended not to use bright, direct lighting and to provide hiding places so the fish feel more secure. They can be kept in regular tap water with a water temperature of 23-27°C. As a preventive measure against Oodinium, 1 teaspoon of salt per 10 liters of water can be used. Weekly water changes of 1/3 are also necessary to avoid and control potential diseases. They eagerly eat all types of live foods. With a monotonous diet, they often lose appetite and gradually die. dH up to 15°, pH 7-8.
Nothobranchius thierryi, Nothobranchius ugandensis, Nothobranchius virgatus.
Nothobranchius orthonotus, palmqvisti, patrizii, polli. 
