Flooded Savanna, Capanaparo river, state of Apure, Venezuela

_th place in Biotope Aquarium Design Contest 2020

Volume: 180 L
Dimensions: 80x60x45 cm
List of fishes:Fishes: 4 young specimens of Mikrogeophagus ramirezi (Myers e Harry, 1948) ,10 Petitella rhodostoma (Ahl, 1924), Invetrebrates: Physa marmorata (Guilding, 1828), Planorbis cf. arnoldi. Ostracods, Cycloops and Tubifex sp. as microinvertebrates
List of plants: Helanthium bolivianum angustifolius, Helianthium tenellum, Eichhornia azurea, (both floating and submersed form), Eichhornia diversifolia, Eleocharis acicularis, Sagittaria sp, Ludwigia inclinata.
Description of decorations: The bottom consists of a layer of peat (2cm) covered with a thick layer (3-5cm) of amber quartz sand (for aquarium use and similar to that shown in video showing the natural biotope), currently partially naturally covered with organic debrys (natural deposit produced by the aquarium) and plant debrys (collected in nature): fallen leaves and broken branches (similar to those shown in video from the natural biotope), Fabaceae pods (similar in shape to those of Erythrina sp.), palm fiber. Hard-scape consists of a few wooden pieces and roots.
Description of equipment: Lighting: 150w “Mars Hydro TS 1000 Full Spectrum LED” (21010 lumens). Photoperiod is 10 hours (set for comfort 10:00-20:00). Filtration: external 3-stage filter: mechanical filter-media (coarse, fine), biological media. Delivery pump 2700 L/ h (Sicce Syncra 3.0) which provide a real water-flow of about 1000 L/h. In/out filter system consist on transparent (unmovable) pipes ,pvc pipes passing through the bottom of the tank and grey pvc junctions (hidden by plants).
Heating: external in-line heat exchanger (Hydor ETH 200) set at 26 °C which is turned on only in winter season.
CO2 cylinder system (turned off in last years) with a Solenoid valve (Whimar) and an external in-line diffuser (JBL ProFlora Direct). CO2 had been erogated from 12:00 to 18:00 (two hours after light was turned on and until 2 hour before light was turned off) in very low amount which never had reached 15mg/L in order not to intoxicate the fishes.
Water parameters: Transparent water obtained by adding buffers to RO water: mineral salts and low concentrated fertilizers. Fertilization were optimized in order to maintain a low nutrient content which drop to zero after one day from its dosing. Temperature: 27.6 ° C (year average, minimum at 26 °C from November to May, maximum at 30 °C in July-August due to summer local high temperature), pH 6.6-7.2, KH 2-3 (HCO3- about 65 ppm), CO2 5-15 mg/L, O2 8 ppm (water oxygen saturation), GH 4, Mg2+ 5 ppm, Ca2+ about 20 ppm (calculated from GH and Mg2+ values), K+ 8 ppm, Fe2+ 0.05 ppm, NH4+ 0 ppm, NO2- 0 ppm, NO3- < 5 ppm, PO43- 0-0.5 ppm, (water parameters were all measured with JBL TestLab).
Additional info: In order to simulate natural habitat, microinvertebrates colonies are weekly restored into the aquarium by fresh inoculums from indoor cultures of Tubifex, Ostracods and Cyclops. All these organism are naturally hunted by M. ramirezi’s which love to catch live food from the debris. Sometimes these live organism are also eaten by tetras, which, always looking for easy food, spy M. ramirezi during the hunt. In case of green water presence during summer (due to the set of high light and high temperatures in summer) a high density colture of Daphnia pulex is added to the tank inside a round fish fry net which protect them from fish attacks. Most of the stem plants have being produced from mother plants kept in this same aquarium which had all reached a total lenght of up 1 meter.
All Mikrogeophagus ramirezi are young specimens born from aquarium kept parents.


Description of the area surrounding the biotope: The Capanaparo River is located in Colombia and western Venezuela and is a moderatly black water, tributary of the lower Orinoco basin. It born in in the Arauca department of Colombia a few kilometers from the border with Venezuela. Its extension is 650 kilometers of total navigable area, of which approximately 225 are in Colombia. Its waters cross the flooded plains in Apure state and the National Park Santos Luzardo (Capanaparo-Cinaruco National Park), then feeds the waters of the Orinoco River. These lands are characterized by the presence of swamps, estuaries and morichales. Around the river we can see an extensive forest of approximately one hundred meters where many animals lives.

The Capanaparo River has a great variety of species, including threatened species like caiman (Crocodylus intermedius), turtle (Podocnemis  unifilis) and river dolphin (Inia geoffrensis). On its banks is located the population of La Macanilla, originally an indigenous community. During the dry season, the river attracts a lot to tourism since it is allowed to practice sport fishing (mostly Cichla orinocensis fish, which here are protected by law and it has helped them from being overfished) and camping on its extensive beaches where you can see sunbathing caimans. During rainy season, in the middle of the river, extensive field of dunes and lagoons are formed.

Most of the Capanaparo river basin, like other lower Orinoco basin tributaries (Apure), is located in a vast seasonal alluvial plain called the llanos, which represents a highly productive ecosystem cover for the vast savanna vegetation.

The population density in the llanos is relatively low and the area is essentially rural. Overall, human influence is not extensive in the basin and the relationship between the river and its floodplain are principally natural.

The hydrological cycle in the river is accompanied by major changes in the dissolved element concentrations. The temporal variability of these variables is controlled by the changes in the flow values, suggesting that a strong diluition effect is produced during the wet season. The annual hydrological regime basically regulates regional and local diversity and abundance patterns. Two hydrological periods are characteristic of the region. Water chemistry varied little between lentic lagoon and lotic channel habitats.

For most of the fish species that live in Venezuela’s low llanos, the habitat they occupy is not a closed system. On the contrary, from a biological point of view, their habitats are intimately connected to the waterways of the Andean Piedmont, and together they form a single large aquatic ecosystem.

The river presents an area of riparian forest with open savannas and associations of morichito palm (Mauritiella aculeata, Arecaceae), with the presence of permanent water (Morichales habitats). These habitats maintain an effective connection with the main channel of the river throughout the year. A rainy period (May-October) in which the riparian forests are flooded and the organisms are dispersed in the flooded savannas where they take refuge and fulfill reproductive and feeding activities. The floods are therefore accompanied by a rapid increase in both the number of specimens and species that migrate over long distances to the flooded savannas. Dense stands of vegetated patches may be essential for survival and maintenance of populations of prey taxa that need to avoid predators, especially during the dry season when predator densities increase. Submerged vegetation, is known to mediate predator-prey relationships via increased structural complexity. The dry period is associated with the continuous descent of water levels, which forces fish and other aquatic organisms to migrate from forests and floodplains to the main channel associated littoral habitats. Here drainage canals discharge water to the main river. Similar ecological events have also been identified in the African floodplains, the Florida Everglades and some areas of the Mississippi River.

Description of the underwater landscape of the biotope: Capanaparo River is a floodplain river, with either clear-water or black-water characteristics of low suspended sediments (high transparency within 1-3 m), low pH values, conductivity, solute, and nutrient concentrations. Three types of habitats were found: 1) open sandy beaches (> 95% of the substrate formed by coarse sandy, nutrient-poor soil), which are located along the main channel of the river; 2) the main channel of the river, which was characterized by moderate currents (about 0.2 m / s), depth between 5 and 12 meters, and generally sandy substrates. 3) blackwater type areas, covered with morichito palm (Morichales), which presented a substrate with a high proportion of organic matter: leaf litter, aquatic grass, branches and large woody debris. Vegetated habitats were defined as having > 90% of coverage by large woody debris derived from riparian vegetation.  Also, the speed of the current of this type of habitat is very slow (< 0.015m / s) and depth about 1 m. These systems have continuous availability of food, supply of material allochthonous, habitat for refuge from predators and reproduction. These factors are probably responsible for the higher species richness found in vegetated habitats. 41 species of fish were only collected in Morichales habitats, indicating the importance of these habitats to maintain fish diversity. In structurally complex habitats, specialist species also can exploit specific food resources to which they are morphologically or physiologically adapted to utilize. For example, in vegetated patches are found a relatively high abundance of small invertivorous cichlids such as Ram cichlid (Mikrogeophagus ramirezi) and small catfishes of the Doradidae family with different body shapes and feeding habits. Although were not evaluated it was apparent that vegetated patches contained a high abundance of shrimps and other macroinvertebrates.

Flooded savannas may present a relative high water current, where dense vegetation grasslands sways rooted in the sandy soil, which is partially covered with organic matter (see Amazon Tropical River Underwater Stock Video Footage 23 and Amazon Tropical River Underwater Stock Video Footage 22 youtube videos). In Flooded savannas some debris typical of Morichales habitat and surrounding riparian forest are hold back by plants. Water is clear, and less acidic, due to the high rainwater seasonal precipitation. Although the low nutrient content of water, its moderate water replacement allow even to high demanding plants to grow (such as Eichornia azurea, E. diversifolia and Ludwigia inclinata). In this area is also possible to find together Morichales and other habitats fishes, like some Hemmigrammus species (actually under the Petitella genus) and many rams (Mikrogeophagus ramirezi), moving to floodplains during wet season. Ram’s habitat is quite variable, due to its extension. Rams are normally found in deep water not more than 60cm, normally about 30cm, in areas with no shade. The habitat present both free swimming and fully covered areas by vegetation that shield from the current and provide shelter. It is precisely within these depths (30-60cm) typical of floodplain shallows during the wet season that can be found large populations of red plants such as Ludwigia inclinata that after reached the surface of the water they develop as floatings and completing their life cyrcle with flowers and seeds. Here an hairgrass lawn (Eleocharis sp.) is a common plant coverage of the sandy bottom.

In this natural habitat the Rams spend their time feeding on the organisms found in organic sediments and showing their territoriality by contracting the fins and expelling other Rams or other fish from their territory. In some occasion the male could show aggressive behavior aganist the partner female too, in order to force her to spawn.

Description of the parameters of the habitat: Not many numerical data were found. The following data were recovered putting together data from of some references. Temperature 26.0 – 31.2°C, pH 5.0 – 7.6, Conducibility 35-60 µS∙cm-1 (at 20°C), TSS (dry residue) 2-15 mg/L, NO3- 7 – 11 µg/L, PO43- 0.9 – 2.7 µg/L, total alkalinity < 0.5 mg/L, Hardness 6 mg/L.

List of fishes and invertebrates occurring in the nature biotope: Within the sub-basins that drain towards the Orinoco, the greatest diversity reported is for the Apure rivers (390 species), Caura (384), Meta (378), Cinaruco (300) and Capanaparo (201). In Capanaparo river, five families grouped the largest number of species: Characidae (29%) and Ciclidae (13%) represented 41% of the total species reported, followed by Doradidae (5%), Anostomidae (5%) and Loricariidae (4%): Hyphessobrycon sweglesi, Moenkhausia copei, Myleus rubripinnis, Petitella rhodostoma, Pygocentrus cariba, Serrasalmus rhombeus, Aequidens diadema, Apistogramma hoignei, Apistogramma hongsloi, Biotodoma wavrini, Cichla orinocensis, Cichla temensis, Heros sp., Mesonauta insignis, Mikrogeophagus ramirezi, Satanoperca daemon, Platydoras costatus, Scorpiodoras heckelii, Anostomus ternetzi, Leporinus fasciatus, Farlowella mariaelenae, Rineloricaria sp., Nannostomus eques, Carnegiella marthae, Electrophorus electricus, Hoplias malabaricus, Potamotrygon motoro, Hoplosternum littorale.

List of plants found in the nature biotope: Llanos plants biodiversity reach 200 species: Cabomba furcata, C. aquatica, Eichhornia azurea, E. crassipes, E. diversifolia, Eleocharis sp. Eriocaulon sp., Helanthium bolivianum angustifolius, Helianthium tenellum, Heteranthera limosa, H. reniformis, Hygrophila guianensis, Lemna sp., Limnobium laevigatum, Ludwigia helmintorrhiza, L. inclinata, L. inclianta var. verticillata, L. sedoides, Najas indica, Nymphaea rudgeana, Pistia stratioites, Phyllanthus sp., Sagittaria guyanensis, Syngonanthus  sp., Utricularia sp.

Threats to the ecology: Venezuela’s environments are affected by several major ecological threats: deforestation, hydroelectric dams, dredging of major rivers for navigation, pollution and overfishing. However, the main threats encountered in the state of Apuré are: widespread deforestation / fire for agricultural purposes and water pollution. Satellite imaging studies have shown that Venezuela is one of the South American countries to have suffered the greatest forest losses. Deforestation in Andean Piedmont causes erosion and silting up of streams and rivers. Riparian forests provide shade and reduce the water temperature in the lowlands. For this reason, deforestation has the side effect of increasing the water temperature and this helps to lower dissolved oxygen levels and accelerate fish deaths from hypoxia. Deforestation, by drastically reducing the amount of water in rivers during the dry season, directly affects the migratory cycle of many fish and concentrates the toxic effects of agriculture (in western llanos this is mainly due to the processing of sugar cane): normally, adult fish from dry season shelters move to seasonally flooded swamps to spawn during the rainy season. Therefore, the induction of severe hypoxia both by water heating and water pollution during the dry season has the potential to completely eradicate entire populations from river basins.

Sources of information:

  1. Personal discussion with Ivan Mikolji, George Fear and Donald Taphorn.
  2. Bittencourt PS, Machado VN,  Marshall BG, Farias TH, Farias IP. Phylogenetic relationships of the neon tetras Paracheirodon spp. (Characiformes: Characidae: Stethaprioninae), including comments on Petitella georgiae and Hemigrammus bleheri. Neotrop. ichthyol. vol.18 no.2, 2020,  Maringá.
  3. Mora, Abrahan & Laraque, A & Moreira-Turcq, Patricia & Alfonso, Juan. 2014. Temporal variation and fluxes of dissolved and particulate organic carbon in the Apure, Caura and Orinoco rivers, Venezuela. Journal of South American Earth Sciences. 54.
  4. Rial AB. Diversity, bioforms and abundance of aquatic plants in a wetland of the Orinoco floodplains, Venezuela. Biota Colombiana, vol. 15, núm. 1, enero-junio, 2014, pp. 1-9 Instituto de Investigación de Recursos Biológicos “Alexander von Humboldt” Bogotá, Colombia.
  5. Lasso CA, Rial A, Colonnello G, Machado-Allison A. Trujillo F. Humedales de la Orinoquia Colombia Venezuela. Instituto de Investigacion de Recursos Biologicos Alexander von Humboldt. 2014.
  6. Montaña, Carmen G.; Layman, Craig A.; Taphorn, Donald C. Inventario de la ictiofauna del Caño La Guardia, afluente del río Capanaparo (cuenca del Orinoco), estado Apure, Venezuela. Biota Colombiana, vol. 11, núm. 1-2, 2010, pp. 75-88 Instituto de Investigación de Recursos Biológicos “Alexander von Humboldt” Bogotá, Colombia.
  7. Lasso CA, Usma JS, Trujillo F, Rial A. 2010. Biodiversidad de la cuenca del Orinoco: bases cientificas para la identificacion de areas prioritarias para la conservacion y uso sostenible de la biodiversidad. Instituto de Investigacion de Recursos Biologicos Alexander von Humboldt, WWF Colombia, Fundacion Omacha, Fundacion La Salle e Instituto de Estudios de la Orinoquia (Universidad Nacional de Colombia). Bogota, D. C., Colombia. 609 pp.
  8. Lehtonen S, Gordon E. Actualización del conocimiento de los géneros Echinodorus y Helanthium (Alismataceae) en Venezuela. Acta Botánica Venezuelica, vol. 33, núm. 2, julio-diciembre, 2010, pp. 249-272 Fundación Instituto Botánico de Venezuela Dr. Tobías Lasser Caracas, Venezuela
  9. Montaña CG, Layman CA, Taphorn DC. Comparison of fish assemblages in two littoral habitats in a Neotropical morichal stream in Venezuela. Neotropical Ichthyology • December 2008
  10. Rial  AB. Flora y vegetación acuática de los Llanos de Venezuela con especial énfasis en el humedal de los llanos de Apure. 2007. pp.99- 106.
  11. Rodriguez MA, Winemiller K, Lewis WM, Taphorn DC. The freshwater habitats, fishes, and fisheries of the Orinoco River basin. Aquatic Ecosystem Health and Management 10. 2007. 140–152
  12. Lasso CA, Mojica JI, Usma JS, Maldonado OJS, DoNascimiento C, Taphorn DC, Provenzano F, Lasso-Alcalá OM, Galvis G, LVásquez L, Lugo M, Machado-Allison A, Royero R, Suárez C,Ortega-Lara A. Peces de la cuenca del río Orinoco. Parte I: lista de especies y distribución por subcuencas
  13. Revista: Biota Colombiana 2004.
  14. Rial AB. Aspectos cualitativos de la zonación y estratificación de comunidades de plantas acuáticas en un humedal de los llanos de Venezuela. Fundacion La Salle de Ciencias Naturales Tomo LX, no 153, enero / junio 2000.
  15. Winemiller K, Taphorn DC, Barbarino DA. Ecology of Cichla (Cichlidae) in Two Blackwater Rivers of Southern Venezuela. Copeia. 1997. 10.2307/1447287.
  16. Winemiller K, Marrero C, Taphorn DC.  Perturbaciones causada por el hombre a las poblaciones de peces de los llanos y del piedmonte Andino de Venezuela. 1996
  17. Kasselmann C. Aquarium Plants. 2020. ISBN: 9783000649127
  18. Rio Capanaparo geographic data  https://geographic.org/geographic_names/name.php?uni=-1387109&fid=6605&c=venezuela
  19. Rio Capanaparo description  http://riosdelplaneta.com/rio-capanaparo/
  20. Flooded savanna drainage canal Biotope, Apure, Venezuela https://www.flickriver.com/photos/mikolji/16465988750/
  21. Flooded savanna drainage canal Biotope, Apure, Venezuela https://www.flickr.com/photos/mikolji/16515468483/
  22. Cichla orinocensis  https://mikolji.com/article/close-encounters-cichla-kind
  23. Rivers in Apure State http://aquatic-experts.com/ESPANOL/rios_del_estado_Apure_ES.html
  24. Flooded areas habitat http://aquatic-experts.com/ESPANOL/areas_inundadas_ES.html
  25. Morichales habitat http://aquatic-experts.com/ESPANOL/morichales_ES.html
  26. Morichales habitat http://biotopeaquarium.freeforums.net/thread/49/examples-biotope-morichales-venezuela-uracoa
  27. Venezuelan aquatic plants list http://aquatic-experts.com/ESPANOL/PLANTAS_DE_AGUA_DULCE_ES.html
  28. Eichhornia azurea https://www.aquatic-experts.com/ESPANOL/Eichhornia_sp_ES.html
  29. Ludwigia inclinata https://www.aquatic-experts.com/ESPANOL/Ludwigia_inclinata_ES.html
  30. Cano la Guardia https://aquatic-experts.com/ESPANOL/rio_cano_la_guardia_ES.html
  31. Cano la Pica https://aquatic-experts.com/ESPANOL/rio_Cano_La_Pica_ES.html
  32. Rio Capanaparo https://aquatic-experts.com/ESPANOL/rio_capanaparo_ES.html
  33. Rio Cinaruco https://aquatic-experts.com/ESPANOL/rio_cinaruco_ES.html
  34. Rio Morichal largo https://www.aquatic-experts.com/ESPANOL/rio_morichal_largo_ES.html
  35. Cichlids https://www.aquatic-experts.com/ARTICLE_swimming_with_cichlids.html
  36. Hemigrammus habitat https://www.aquatic-experts.com/ARTICLE_The_Half_Red_Hemigrammus_a_new_species.html
  37. Hemigrammus rhodostomus https://www.aquatic-experts.com/Hemigrammus_rhodostomus.html
  38. Hemigrammus sp. https://www.aquatic-experts.com/Hemigrammus_sp_CLP.html
  39. Hemigrammus strictus https://www.aquatic-experts.com/Hemigrammus_stictus.html
  40. Mikrogeophagus ramirezi https://www.aquatic-experts.com/Mikrogeophagus_ramirezi.html
  41. Mikrogeophagus ramirezi https://mikolji.com/article/ram-cichlid-mikrogeophagus-ramirezi-wild
  42. similar habitat https://www.aquatic-experts.com/Pristella_sp_1.html
  43. similar habitat https://www.aquatic-experts.com/Astyanax_bimaculatus.html
  44. similar habitat https://www.aquatic-experts.com/Catoprion_mento.html
  45. similar habitat https://www.aquatic-experts.com/Potamotrygon_orbignyi.html
  46. TARGET BIOTOPE. Flooded Savanna Habitat. Amazon Tropical River Underwater Stock Video Footage 22 https://www.youtube.com/watch?v=ahSLPwkhejY
  47. TARGET BIOTOPE. Flooded Savanna Habitat from min 5.50. Amazon Tropical River Underwater Stock Video Footage 23 https://www.youtube.com/watch?v=Vj8kXsaszbE
  48. from Apure to Capanaparo https://www.youtube.com/watch?v=tfphOsbn_2c
  49. rio Capanaparo https://www.youtube.com/watch?v=hfO7La2480o
  50. Ciranuco natural National Park https://www.youtube.com/watch?v=lTQHeaHfSEw
  51. rio Cinaruco https://www.youtube.com/watch?v=aYervXuqbu8
  52. rio Cinaruco https://www.youtube.com/watch?v=3NfQRi5oT6Q
  53. Morichales habitat https://www.youtube.com/watch?v=_agTo67qc1A
  54. Freshwater Natural Aquarium Documentary https://www.youtube.com/watch?v=TzzJU810AIk
  55. similar habitat at min 12-15 https://www.youtube.com/watch?v=x4rZAHXtlsE&t=774
  56. similar habitat at min 34-36  https://www.youtube.com/watch?v=cZUmH9SRFgs&t=2005
  57. Mikrogeophagus ramirezi habitat https://www.youtube.com/watch?v=LpGyXBNpERw&list=PUDIt33wrOT25jwzucibiGUw&index=13 other
  58. other M. ramirezi habitat https://www.youtube.com/watch?v=L05gM9OGTvo
  59. other M. ramirezi and tetra habitats

Comments of the members of the jury of Biotope Aquarium Design Contest 2020