Upper Nile. Swamps near Sedd region in southern Sudan

The 30th place in the qualifying stage of the Biotope Aquarium Design Contest 2015

 Russia. Svetlana Kirillova

Volume: 300 L
List of fishes: Protopterus aethiopicus
List of plants: Pistia stratiotes, Cyperus sp.
Biotope description: The Nile River is the longest river of the African continent. It originates in the East African highlands (Kagera River), flows through the Lake Victoria and Albert, after the confluence of the Sobat river is called the White Nile, in Khartoum takes the main tributary – Blue Nile and being called the Nile flows to the Mediterranean Sea where it forms a vast delta. On the plains of Sudan the Nile is called Bahr al Jabal (Mountain River), it crosses the Sedd marshes, where it flows into the River of Gazelles (Bahr al Ghazal) and loses half its water to evaporation and absorption by its abundant vegetation. Here, huge masses of algae, floating plants and papyrus clutter the channel, and the river spreads widely and forms many arms. Spills are contributed by heavy floods in the region of Sudan, they occur in summer and autumn. All this creates conditions for existence of diverse and numerous aquatic fauna. There are many species of fish here: catfish, cichlids, polypteruses, and among them surprising lungfish – Protopterus. Protopterus, in addition to its gills, has a double lung, and adult fish uses mainly pulmonary respiration, through the gills it consumes less than 10% of oxygen. Taking breath Protopterus sticks out of the water its upper lip, on its inside surface openings can be seen through which air enters the lungs. The throat of the fish in this moment gets much bigger. In most parts of its habitat Protopter live in temporary ponds, drying up in the dry season, and hibernate for a period of drought, getting into the soil to a depth of 25-50 cm, forming a cocoon of dried mucus around the body, that prevents moisture loss, with only a hole of 1-5 mm for breathing against the fish’s mouth. Typically the hibernation lasts for 6-9 months, during it Protopterus loses around 20% of its weight and shrinks. In its tissues an amount of urea accumulates that would be lethal to most vertebrates (1-2% of body weight). However, when the water comes, Protopterus wakes up safely. The recorded length of hibernation was shown by brown Protopterus, who slept without harm more than 4 years. At the same time Protopterus living in perennial reservoirs, for example, in the Great Lakes of Central Africa, do not hibernate. The same can be said about Protopterus in aquarium. For example, the large Protopterus you can see on the pictures lives without hibernation in an aquarium for about 30 years. Its length is now 87 cm. This species reaches two meters long in the wild. So it is not so much. But colours, more bright in young fish, became darker and more uniform with age. For obvious reasons Protopterus is the only inhabitant of the aquarium, since small fish is its food, and it can damage big fish. Also in the aquarium instead of Cyperus papyrus, growing in this biotope and reaching a height of 3 m, a smaller species of Cyperus was used.