Morichal Largo River, Orinoco River basin, Venezuela

59th place in Biotope Aquarium Design Contest 2019

Turkey. Oğuzhan Çepni

Volume: 84 L
Dimensions: 53×40×40 cm
List of fishes: Paracheirodon Simulans, Mikrogeophagus Ramirezi.
List of plants: Cabomba aquatica, Ceratophyllum Demersum, Myriophyllum Aquaticum, Echinodorus sp., Pistia Stratiotes, Lemna Minor.
Description of decorations: In this aquarium, wood, leaves and plants suitable for the region were used. The bottom contains sediment and filamentous algae, as you will see in the source video. In the same way dirty on the branches. This aquarium mimics the coastal area of ​​the river.
Description of equipment: The aquarium is equipped with Dophin A3000 350 lt/h. The aquarium lighting is, 16 watt power led system.
Water parameters: Water temperature is 25 °C, pH is 6,4.
Additional info: 20% water change per week.


Description of the area surrounding the biotope: The Morichal Largo River is located in Llanos, north of Venezuela. It takes its name from a woman. In the vicinity are various Morichal Palms and deciduous trees.
Orinoco River, Spanish Río Orinoco, major river of South America that flows in a giant arc for some 1,700 miles (2,740 km) from its source in the Guiana Highlands to its mouth on the Atlantic Ocean. Throughout most of its course it flows through Venezuela, except for a section that forms part of the frontier between Venezuela and Colombia. The Orinoco and its tributaries constitute the northernmost of South America’s four major river systems. Bordered by the Andes Mountains to the west and the north, the Guiana Highlands to the east, and the Amazon watershed to the south, the river basin covers an area of about 366,000 square miles (948,000 square km) It encompasses approximately four-fifths of Venezuela and one-fourth of Colombia. For most of its length, the Orinoco flows through impenetrable rain forest or through the vast grassland (savanna) region of the Llanos (“Plains”), which occupies three-fifths of the Orinoco basin north of the Guaviare River and west of the lower Orinoco River and the Guiana Highlands. Since the 1930s this region has been developing into one of the most industrialized areas of South America. Below the town of Esmeralda, some of the waters of the Orinoco flow south into the Casiquiare River (Brazo Casiquiare; sometimes called the Casiquiare Channel). This channel, a feature peculiar to the Orinoco River system, is a natural passage that flows generally south until it combines with the Guainía River to form the Negro River, thus linking the Orinoco and Amazon river systems. The Llanos encompasses nearly all of the western lower Orinoco basin, occupying some 220,000 square miles; most of the land is less than 1,000 feet above sea level. The High Plains (Llanos Altos) are most conspicuous near the Andes, where they form extensive platforms between rivers and are some 100 to 200 feet above the valley floors. Away from the mountains they are increasingly fragmented, as in the dissected tableland of the central and eastern Llanos (the Sabana de Mesas) and the hill country (serranía) south of the Meta River in Colombia. The Low Plains (Llanos Bajos) are defined by two rivers, the Apure in the north and the Meta in the south. The lowest portion of the Llanos is an area that lies to the west of the lower Orinoco valley; this area is converted annually into an inland lake by flooding. The climate of the Orinoco basin is tropical, with the seasons marked by differences in rainfall rather than in temperature. The year is divided into two seasons—rainy and dry (locally known as winter and summer)—the former extending from April to October or November and the latter most marked from November through March or April. The wet and dry seasons result from the annual migration of the intertropical convergence zone, a low-pressure trough between the hemispheric easterlies, or trade winds; the passage of the zone northward from its summertime position south of the Equator brings the rainy winter period. In contrast to precipitation, temperature differences in the basin are slight throughout the year; and no month averages more than 69 °F (21 °C) or less than 64 °F (18 °C). Whatever the average temperature, there is little difference from month to month. The only marked variation is from day to night, being greater than that from month to month. On the Llanos, daily maximum temperatures rise above 95 °F (35 °C) in the dry period; the dry winds and nocturnal cooling bring relief with normal minimum temperatures between 65 and 75 °F (18 and 24 °C). More than 1,000 species of birds frequent the Orinoco region; among the more spectacular are the scarlet ibis, the bellbird, the umbrella bird, and numerous parrots. The great variety of fish include the carnivorous piranha, the electric eel, and the laulao, a catfish that often attains a weight of more than 200 pounds. The Orinoco crocodile is one of the longest of its kind in the world, reaching a length of more than 20 feet. Among other inhabitants of the rivers are caimans (an alligator-like reptile) and snakes, including the boa constrictor. The arrau, or side-necked turtle, the shell of which grows to a length of about 30 inches, nests on the sandy islands of the river. Insects include butterflies, beetles, ants, and mound-building termites.

Description of the underwater landscape of the biotope: Under the river water, there are branches and leaves. There are tree roots on the river bank. Palm leaves decompose falling into water. There is rotten leaf residue on the ground. Aquatic plants are found in most parts of the river. The river is fresh water.

Description of the parameters of the habitat: Water temperature is 24-28 °C, pH is 5.2-6.5.

List of fishes and invertebrates occurring in the nature biotope: Acestrorhynchus falcatus, Acestrorhynchus microlepis, Gnathocharax steindachneri, Heterocharax virgulatus, Anostomus ternetzi, Apistogramma guttata, Sternarchorhynchus mendesi, Mesonauta Insignis, Mikrogeophagus Ramirezi, Paracheirodon Simulans, Cichlasoma Bimaculatum, Crenicichla sp., Heros Severus, Hoplias Malabaricus, Nannostomus sp., Rineloricaria sp., Ancistrus sp.

List of plants found in the nature biotope: Phyllanthus Fluitans, Egeria Densa, Pistia Stratiotes, Ceratophyllum Demersum, Salvinia Auriculata, Sagittaria Subulata, Hydrocotyle Leucocephala, Myriophyllum Aquaticum, Lemna minör, Echinodorus sp., Cabomba Aquatica, Pistia Stratiotes, Mayaca Fluviatilis.

Threats to the ecology: Abundant water in the Orinoco River Basin supports the needs of people, agriculture, energy and industry (oil and gas) that are vital for Colombia’s social and economic development. But the basin faces increasing pressures from the expansion of mining (942 concessions for 2014), oil and gas (8 million ha under exploration), agro-industry (320,829 ha), and infrastructure, which if not adequately planned and implemented can disrupt the hydrology and ecosystem services of the region. Additionally, the Orinoco Basin’s seasonal rainfall patterns will potentially face further extremes and unpredictability from climate change, leading to greater droughts, flooding, and fires. Maintaining the health of the Orinoco River Basin is vital to support adequate water and services critical for people, the economy, and nature.

Sources of information:
Region information:
Fish and plant list:
Mikrogeophagus Ramirezi and Paracheirodon Simulans:

Comments of the members of the jury of Biotope Aquarium Design Contest 2019