Central and West Africa.
Within Central Africa, Cameroon, Equatorial Guinea, Gabon, Congo, Zambia, Zaire, and Angola are located wholly or partially. External drainage is carried out mainly by five largest rivers – the Congo, Nile, Niger, Zambezi, and Orange. These rivers are transiting, cross several climatic zones, and have a complex runoff regime. This is especially true for the Congo, Nile, and Niger rivers – the longest rivers whose basins have the largest area.
A characteristic type of African landscape is the savanna, overgrown with tall grass, with groups of individual trees, primarily umbrella acacias. To the north and south, the savanna turns into strips of dry steppes, and beyond them into the desert. If rivers are found here, in most cases they have drying riverbeds. These zones are characterized by the periodic alternation of the summer rainy season with the winter dry season. Such alternation causes the formation of so-called periodic waters, known as habitats for egg-laying killifishes (genera Aphyosemion, Nothobranchius).
In addition to humid tropical forests, there are savannas with large and small ponds, rivers, and streams, as well as depressions and ditches near the coast, where fresh water mixes with sea water. Rivers originate from mountain springs and swamps, have a rocky character with numerous waterfalls. Falling from the mountains, they rush down narrow canyons to the plains, where they turn into wide, deep, and lazily flowing rivers. When analyzing the waters inhabited by dwarf cichlids, killifishes, barbs, and characins, which are so popular among aquarists, their extreme softness and (most often) acidic reaction catch the eye. This also applies to the water-rich regions of the Zaire (Congo) basin.
Small rivers in the northeast of the country belong to the Nile basin. The Nile is the longest river in the world, starting on the East African Plateau with the Kagera River and flowing through Lake Victoria, Kyoga, and Albert, into which the outflow of Lake Edward is directed. Descending the ledges of the plateau, the river forms a series of waterfalls. Below the confluence with the Sobat, the river is called the White Nile. Along the low banks of the Nile in Sudan, thickets of reeds and papyrus stretch. Near Khartoum, the White Nile merges with the Blue Nile, which originates on the Abyssinian Highlands as a small stream flowing into Lake Lake Tana. After the confluence of the White and Blue Nile, the river is simply called the Nile. Below Cairo begins the mouth, having the shape of a delta almost equal in area to the Crimean Peninsula.
The runoff of the Nile is subject to sharp seasonal fluctuations. The rise in the river level begins in June and September and reaches its maximum value in the lower course. The main stream of the Nile is inhabited by at least 112 species of fish, 16 of which are not found anywhere else. The most important freshwater fish of Africa belong to cichlids (Tilapia). They multiply quickly, grow fast, occur in large numbers, are suitable for human consumption, and live in almost every river, stream, and lake. Other giant fish are also found in African rivers. The African sharptooth catfish (Clarias), a very large representative of the Clariidae family, can grow up to 1 m.
Hydrographically, the main part of Central Africa belongs to the Congo (Zaire) River basin, the most water-abundant and second longest river in Africa. Its bed, predominantly with low and flat, often swampy banks, is a chain of lake-like expansions (up to 15 km) separated by relatively narrowed (up to 1.5-2 km) sections. The Congo describes a huge arc, convex to the north, and crosses the equator twice. Descending into the Congo basin, the river forms a series of waterfalls and rapids; another series of waterfalls marks the lower course of the river in a narrow valley breaking through to the ocean. Unlike other tropical rivers, it is characterized by a fairly stable water regime due to alternating rainy seasons in different parts of the basin.
Tributaries: Right: Aruwimi, Rubi, Mongalla, Oubangui (Uele), Sangha-Mbaéré, Likouala-Lekoli, Alima, Lefini; Left: Lomami, Lulongo, Ikelemba, Ruki, Kasai with Sankuru and Kwango, Lualaba. It flows into the Atlantic Ocean with a wide (11 km) and deep channel. The territory extending from the coast of Guinea for approximately 5000 km to the east and about 1600 km from north to south and adjacent to the forested bed of the Congo River is occupied by virgin tropical jungle forests, through which small rivers and streams flow, whose course is interrupted by small lakes and backwaters.
The Niger ranks third among other African rivers in length (after the Nile and Congo). On its way from its sources in the Guinea Highlands to its mouth on the coast of the Gulf of Guinea, the Niger describes an arc, the apex of which, the so-called Niger Bend, almost reaches the borders of the Sahara. The upper and lower reaches of the Niger lie in subequatorial and equatorial regions, in the band of heavy summer rains, while the middle course of the river is in very arid, semi-desert areas.
The Zambezi is the fourth longest river and basin area in Africa. Nevertheless, it is a powerful water flow and ranks second after the Congo in terms of annual runoff volume. The Zambezi originates on the Lunda-Katanga plateau. In its upper course, right up to Victoria Falls, it is a wide and calm river whose flow in summer, during the rainy season, is lost in the vast swamps of a wide floodable valley. The river is most full-flowing in the southern “summer”, from November to March, after which there is a rapid drop in level until the next November rise. One of the brightest features of the Zambezi is Victoria Falls, one of the greatest waterfalls in the world. The width of the waterfall is approximately 1800 meters, the height is 128 meters. Islands are located along the course of the river, their number increasing as one approaches the waterfall.
The water bodies of West Africa are the homeland of many fishes of the killifish family (Cyprinodontidae), egg-laying toothcarps. The landscape of the African continent where killifishes are distributed is most often a savanna. Abundant grass cover, individual trees or groups of trees and bushes. The savanna climate is characterized by uneven precipitation throughout the year: the rainy season alternates with the dry season. Usually, the drought period lasts 1-2 months, and in some regions – several months. At this time, many water bodies dry up, especially shallow ones. Fishes inhabiting drying rivers, streams, lakes, and puddles usually perish. However, the eggs they laid are preserved and incubated in the bottom mud. These eggs can last quite a long time. With the onset of the rainy season, water bodies fill with water, larvae hatch from the eggs, which then turn into fast-growing fry. Life in the water resumes. Now, until the next dry period, the fish must grow, reach sexual maturity, and spawn. The distribution areas of killifishes also include humid tropical forests, the zone of which extends along the southern coast of West Africa and in the western part of Central Africa. In these evergreen forests, there are also temporary water bodies, but streams and rivers where water is present all year round can also be found.
The waters of Central and West Africa are rich in fish, many species of which are aquarium fish or have local commercial importance (genera Tilapia, Synodontis, Labeo). West African fishes are not as widely represented in our aquariums as South or North American ones. The reason is also that the number of colorful and small-sized species in this region is small. Most dwarf cichlids, and in particular representatives of the genera Chromidotilapia, Hemichromis, Nanochromis, and Pelvicachromis, are supplied to the market from Asia. Only three cichlids are regularly imported: Steatocranus casuarius, S. tinanti, and Teleogramma brichardi.
Among the river cichlids of Africa, one would like to draw attention to Hemichromis. Among several species of Hemichromis, the jewel cichlid and the red chromis (Hemichromis bimaculatus and lifalili) stand out for their special beauty. These fishes are bright, ranging in color from olive-brown to red with many shiny blue dots all over the body. Caught in different areas, they may have minor color variations. Representatives of small West African cichlids, such as Thysochromis, are much less common among the general mass of aquarists. This is already the sphere of activity of cichlid collectors.
Some species of dwarf cichlids, primarily representatives of the genera Teleogramma, Steatocranus, Lamprologus, Pelvicachromis, Parananochromis, Nannochromis, Limbochromis, Anomalochromis, etc., live among the swift water currents of fast rivers and streams. They inhabit forest water bodies of West Africa, are analogs of South American dwarf cichlids, and have similar environmental requirements, and therefore they can be kept in the same aquarium. Local fish are recommended to be combined in aquarium water with their South American relatives.
The least expensive “Africans” are river representatives of Africa’s aquatic fauna – Pelvicachromis (kribensis), Hemichromis (jewel cichlids, red chromises), and tilapias (river and lake). Hemichromis spawn on stones, Pelvicachromis in caves. Parents care touchingly for their fry: chew found food into small pieces for them, lead them on walks, and protect them from any enemies. When a pair of cichlids breeds fry in an aquarium, all other inhabitants try to stay away from them so as not to catch the eye of the excited and therefore very aggressive parents.
The setup and maintenance of the aquarium, as well as the feeding characteristics of West African dwarf cichlids, do not fundamentally differ from their South American counterparts. The natural habitats of these cichlids are located equatorward from southern Guinea, Sierra Leone, and Nigeria, continuing further south to Congo and Angola. The most significant elements from a design perspective are large stones and driftwood. These stones and driftwood are arranged so that they serve as territory dividers for the fish. It is better to use fine substrate. Plants should be planted densely along the edges.
Water in most natural habitats is soft, slightly acidic with pH 6.2-6.8. In some cases, fish are also found in brackish water, so adding 2-3 teaspoons of sea or table salt per 10 liters of water in the aquarium has a beneficial effect on the well-being of the fish (especially wild ones not adapted to aquarium life), as well as on the development of eggs and larvae. The water in the aquarium should be quite soft and slightly acidic or neutral. The temperature optimum is 26-27°C. River African species easily withstand water acidification below 7.0, but still feel better in alkaline water. It is advisable to ensure a high oxygen content, but strong water currents should be avoided, as these species prefer quiet places.
The fecundity of the fish is generally low and rarely exceeds 150-200 eggs per spawning. The fry are large and active, so raising them is not difficult. The parents actively care for the young, demonstrating, in the vast majority of cases, exemplary behavior from both males and females. Sexual dimorphism is well pronounced. Females are generally smaller, brighter colored, and initiate courtship first. A characteristic harem breeding behavior is also noted for some of the West African cichlids mentioned above.
Madagascar Island.
Madagascar (native Nosin Dambo — island of boars) is the fourth largest island in the world, located in the Indian Ocean off the east coast of Africa, separated from it by the wide (up to 400 km) Mozambique Channel. The coastline is slightly indented. The western coast 
is fringed with mangrove vegetation, the eastern with coral reefs. The island is home to the Republic of Madagascar, which also occupies several neighboring islands (Nosy Be, Nosy Mitsio, Nosy Vourouna, Nosy Vau, Nosy Mangabe, Nosy Lava). The area of the island is 590 thousand sq. km. The length is about 1600 km, width is over 600 km. There are assumptions that twenty million years ago Madagascar separated from the African continent, and that its isolation led to the emergence of a separate zoogeographic zone.
The animals of the island are clearly different from African ones. Although Madagascar is located close to Africa, the animal and plant world of the island is unique. Madagascar is home to a small number of endemic cichlid genera, including Ptychochromis and Paratilapia. Most species are endemic. Madagascar is poor in fish. The evolution of the species living here began in the sea, and only over time did they adapt to a new freshwater environment (secondary freshwater fishes). Their origin is betrayed by a double dorsal fin and the ability to live in brackish coastal waters, like many fishes of Australia, their relatives.
The climate is tropical. The central part of the island is occupied by the Ankaratra high plateau, sloping gently to the west and dropping steeply to the lowlands of the east coast. The extreme south of the island is often classified as subtropical. The eastern part of the country is the rainiest; areas of humid tropical forests have survived on the eastern slopes of the plateau. Precipitation is 1500 mm per year, in places 3000 mm. The southern part of the country, on the contrary, is very arid – a desert with aloes and cacti. Rivers flowing into the Indian Ocean are generally short and rocky, rich in hydroenergy resources, and full-flowing throughout the year.
Eastern rivers: Mananara, Mangoro, Maningri, Bemarivo, Ivondro, and Mananjary. Rivers flowing to the west coast and pouring their waters into the Mozambique Channel are generally longer and have a less rapid current than their eastern counterparts, due to the more gentle slope of the central highlands toward the west. Western rivers: Sambirano, Mahajamba, Betsiboka, Mania, North and South Mahavavy, Mangoky, Onilahy, Ikopa, and Mandrare.
There are three large lakes in Madagascar: Lake Alaotra (900 sq. km), Lake Kinkony (100 sq. km), and Lake Ihotry (96 sq. km). The eastern Maningri River also originates from Lake Alaotra. The northwestern and western river basins have a higher pH than the eastern rivers. Previously, the island was “all covered in greenery”, but now most of the forests have been cut down. A little greenery remains only in the east, where a unique tropical forest grows. It is cut through by the Pangalanes Canal, which stretches from Toamasina to Manakara for 700 km. The canal, unlike the Dead Lake (near the capital), is very densely populated: millions of birds and fish live here, and the surrounding forests are full of rare animals. The average winter temperature (July) is 20°C, summer (January) up to 30°C.
Territorial behavior of fish. Feeding and spawning territory.
