Amazon oxbow lake biotope aquarium, a freshwater habitat in Peru

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Peruvian Amazon river Aerial view of a meandering river in the rainforest of Peru. If you look closely, two oxbow lakes are visible towards the center of the image. One is considerably "darker" than the other, but both are isolated from the main channel of the river.

BIOTOPE AQUARIA

A biotope aquarium is set-up to simulate a natural habitat. The fish, plants, water chemistry, light conditions, and tank furnishings are similar to those that can be found in a specific natural setting.

OXBOW LAKE IN SOUTHWESTERN PERU

The southeastern part of Peru is arguably the most biodiverse place on the planet. This biological wealth extends to the river systems found in this tropical rainforest environment.

This biotope profile will look specifically at two oxbow lakes found along the Madre de Dios and Tambopata rivers in the Madre de Dios river system upstream of Puerto Maldonado.

Oxbow Lakes

Virtually all lakes in this part of the Amazon are oxbow lakes. An oxbow lake is a crescent-shaped lake formed when a river changes course. In lowland Amazonia where soft alluvial soils dominate, meandering rivers gradually shift due to erosion and sediment deposition. Oxbow lakes typically form when loops in the river become so extreme that the main channel erodes a new straighter route, leaving the river bend apart from the river. As time passes, the oxbow lake becomes increasingly distant from the main channel. Water conditions change as the water stagnates.

The characteristics of an oxbow lake generally depends on its age. Younger oxbow lakes may be "flushed" by river currents, especially during the flood season. These lakes tend to be slightly more turbid (less transparent) and less acidic than older lakes more distant from the river channel.

Oxbow Lake Characteristics

Depth: Oxbow lakes generally range in depth from 16 feet (5 meters) during floods to less than 6 feet (2 m) at low water.

Thermal stratification: Oxygen and temperature tend to decrease with depth in lakes due to thermal stratification whereby cooler waters do not mix with warmer waters. Thermal stratification is more common in older, more isolated oxbow lakes.

Temperature: According to Amazon Headwaters, a book on the rivers of southeastern Peru, the average temperature of oxbow lakes is 76-80 degrees Fahrenheit (24.6-26.6 degrees Celsius). Oxbow lakes are generally warmer than nearby river channels and shaded forest streams. Temperature rises during the low water period.

Water chemistry: According to Amazon Headwaters, the pH of oxbow lakes ranges from 5.4-6.8 while conductivity is 40-68. pH and conductivity rise during the low water period, possibly due to "increased phytoplankton production." Water transparency also increases at this time.

Substrate: The substrate consists of mud with overlaying organic matter and vegetation in varying states of decomposition. There is a fair amount of submerged wood.

Other wildlife: Both oxbow lakes are inhabited by families of giant river otters. Giant river otters are the top predators in these ecosystems, feeding on 5-10 kg of fish per day. Other non-fish predators of resident fish are primarily birds. Tambopata (650 species) and Manu (1000 species) are incredibly rich with bird life.

Aquatic Plants

Underwater shot of Bladderwort (top) and Victoria cruziana (bottom) Bladderwort, Utricularia foliosa is especially abundant in this habitat.

Oxbow lakes in this region have considerable aquatic plant growth. Most conspicuous are free-floating plants including Eichhornia, Pistia, Salvinia, Victoria cruziana, and Bladderwort (Utricularia foliosa), which grows densely and extensively in the lakes. Amazon sword plants (Echinodorus sp.), Vallisneria, Panicum, and Hymenachne were also present, though in lesser numbers. According to Amazon Headwaters, there are about 35 species of "aquatic herbs and shrubs that are characteristic of floodplain lakes of the rio Madre de Dios lowlands."

Surrounding vegetation: The oxbow lake is surrounded by reeds. There are thick floating plants where the lake narrows.

Tank setup

Tank size will depend on the type of fish you plan to keep in your biotope aquarium. If you are going with smaller tetras, catfish, and Apistogramma then you can use a smaller tank than if you plan to go with larger cichlids and characins.

Current: Direct filter outflows to minimize current. Oxbow lakes are quite still.

Lighting: Bright overhead lighting. You can moderate lighting with some floating plants if desired.

Layout: Dense planting along the sides and rear of the tank with open swimming areas. Wood can be used as well.

Substrate: Fine gravel or sand is acceptable since you probably don't want to use decaying leaf matter and mud which is naturally found in this biotope.

Other notes: You might consider using some peat moss in your filtration system to reduce the pH and soften the water. Peat moss can also mimic the slightly tea-colored water conditions that result from the inflow of blackwater streams.

Fish suitable for aquariums

The rio Madre de Dios probably has more than 600 species, many of which have yet to be described according to Amazon Headwaters. Detritus-feeders, invertebrate-feeders, and seed- and fruit-eating species are abundant in the system.

The aquarium fisheries trade began in the department of Madre de Dios in 2002 according to Amazon Headwaters. The book says the rio Madre de Dios headwaters regions has advantages when compared with aquarium trade fisheries in other parts of the Amazon, namely that the seasonal high water period is "neither too deep nor too long to prevent aquarium trade fisherman from working during the rainy season. Elsewhere in the Amazon Basin aquarium trade fisheries largely stop during the flooding season." Further, the rio Madre de Dios watershed had a large number of endemic species, some of which are small and decorative enough to be attractive as aquarium fish. The book lists the following genera as promising for the aquarium trade: Abramites, Corydoras, Pterolebias, Apistogramma, Crenicichla, Mesonatua, Carnegiella, Gymnocorymbus, Hemigrammus, Tyttocharax, Tyttobrycon, Pyrrhulina, Ancistrus, Hypostomus, Pimelodella, and Pimelodus.

The following fish were observed by boat in the oxbow lakes of the rio Madre de Dios (near Manu National Park) and the rio Tambopata (Tres Chimbadas lake):

• Freshwater Stingray (Potamotrygon motoro)
• Hatchetfish (Carnegiella or Thoracocharax sp)
• Bloodfin (Aphyocharax sp.)
• Moenkhausia (Moenkhausia sp.)
• "Head-and-tail-light"-like tetra (Hemigrammus ocellifer sp.)
• Black piranha (Serrasalmus rhombeus)
• Pacu (Piaractus brachyponus)
• Rineloricaria or Farlowella catfish
• Pike Cichlid (Crenicichla semicincta)
• Festive Cichlid (Mesonauta festivum)
• Aequidens tetramerus or Bujurquina or Cichlasoma

Mesonauta festivum was the most obviously abundant fish as viewed from the boat. Bloodfins and Moenkhausia were also common. Hatchetfish were found near reeds along the shoreline, while a stingray was seen partially buried in a muddy beach area.

FRESHWATER FISHES OF THE TAMBOPATA NATIONAL RESERVE
Compiled by Mario Napravnik

CHARACIDAE (72) Acestrocephalus boehlkei Acestrorrhynchus lacustris Cachoro, Pike characin Aphyocharax pusillus Bloodfin Aphyocharax alburnus Bloodfin Aphyocheirodon sp Astyanaclnus multidens Aslyanax abramis Astyanax anteroides Aslyanax bimaculatus Astyanax fasciatus Two spotted Astianax Silvery tetra Astyanax maxiumus Bario steindachneri Blotch tailed bario Brachichalcinus copei Brycon erythropterum Sabalo cola roja Bryconacydnus ellisi Bryconamencus pachacuti Bryconops melanurus Tail light tetra Characidium fasciatus Charax gibbosus Glass Headstander Charax tectifer Glass Headstander Cheirodon fugitiva Cheirodon piaba Cheirodon ait. notomelas Creagrutus affinis Creagrutus anary Creagrutus beni Ctenobrycon hauxwellianus Galeocharax gulo Gephyrocharax sp Gymnocorymbus temetzi Black widow, Skirt Tetra Gymnocorymbus thayeri Hemibrycon jelskii Hemibrycon jabonero Hemigrammus lunatus Hemigrammus ocellifer Head and tail light tetra Hemmigrammus sp Holoshestes heterodon Hydroyicus sconberoides Hyphessobrycon agulha Red tailed flag tetra Hysteronotus sp Knodus aff. beta Knodus gamma Knodus megalops Knodus aff. moenkhausii Knodus smitthii Knodus sp Leptagoniates aff. pi Moenkhausia barbouri Moenkhausia comma Moenkhausia dichroura Spot tailed Moenkhausia Moenkhausia jamesii Moenkhausia oligolepis Glass tetra Moralesia tectifera Myleus rubripinnis Othonocheirodus lethostigmus Paragoniates alburnus Phenacogaster pectinatus Piabina beni Piaractus brachyponus Pacu Pigocentrus nattereri Red piranha Poptella compresa Prionobrama filigera Glass bloodfin Raphiodon vulpinus Chambira Rhynobrycon negrensis Roeboides affinis Glass characin Roeboides myersii Glass characin Salminus aflinis Serrasalmus humeralis Piranha Serrasalmus rhombeus Black piranha, Spotted piranha Serrasalmus spilopleura Fire mouth piranha Tetragonopterus argenteus Triportheus albus Sardina, sapanama Triportheus angulatus Sardina, Narrow Hatchetfish, sapanama Tyttocharax sp Bristly mouthed tetra

GASTEROPELECIDAE (3) Hatchet fish Carnegiella schereri Hatchet lish Carnegiella myersii Myersi hatchetfish Thoracocharax stellatus Silver hatchetfish ERYTHRINIDAE (3) Trahlras, huasacos Erythrynus eryihrinus Short finned trahira Hoplerytrhinus unitaeniatus Trahiras, huasacos Hoplias malabaricus Fasaco, Tiger fish, trahira LEBIASINIDAE (1) Pyrrhulina Pyrrhulina vittata Banded pyrrhulina PROCHILODONTIDAE(2) Prochilodus mariae Prochilodus nigricans CURIMATIDAE (5) Curimata sp Cyphocharax sp Steindachnerina dobula Steindachnerina guentheri Steindachnerina hypostoma ANOSTOMIDAE (3) Leporinus Leporinus friderici Friderici leporinus Leporinus striatus Striped leporinus Leporinus yophoru GYMNOTIDAE (2) Knife fish Gymnotus carapo Banded Knife fish Gymnotus coatesi Knife fish STERNOPYGIDAE (2) Knife fish Stemopygus macrurus Ghost Knife fish Sternopygus virescens Knife fish HYPOPOMIDAE (2) Knife fish Hypopomus muelleri Knife fish Hypopomus sp Spoted knife fish ELECTROOPHORIDAE (1) Electric eel Electrophous electricus Electric eel RHAMPHICHTHYIDAE (1) Gymnorhamphichthys sp POTAMOTRIGONIDAE (1) Potamotrygon motoro Freshwater Stingray ENGRAULIDAE (3) Anchoviella carrikeri Anchoviella guianensis Lycengraulis batessi ASTROBLEPIDAE (1) Astroblepus sp RIVULIDAE (1) Rivulus urophtalmos SCIAENIDAE (1) Pachyurus schomburgkii Amazon croaker SYNBRANCHIDAE (1) Synbranchus marmoratus Atinga, Marbled Eel CICHLIDAE (9) Aequidens tetramerus Saddle Cichlid Apistogramma luelingi Apistogramma urteagai Bujurquina cordemadi Bujurquina tambopatae Tambopata Flag Cichlid Cichlasoma boliviense Crenicichla semicincta Pike Cichlid Mesonauta festivum Festive Cichlid Satanoperca jurupari Jurupari, Eartheater, Demon eartheater

DORADIDAE (1) Talking catfishes Trachydora nattereri Talking catfish AUCHENIPTERIDAE(2) Driftwood catfishes Auchenipterus nuchalis Trachelyopterus sp ASPREDINIDAE (1) Banjo catfish Dysichtys sp Smooth banjo catfish PIMELODIDAE (15) Antenna catfishes Brachypatystoma sp Zungaro, Gilded catfish Brachypatystoma filamentosum Salton, Gilded catfish Brachypatystoma flavicans Dorado, Gilded catfish Cheirocerus eques Goslinea platinema Mota flemosa Heptapterus sp Impartinnis sp Hanhortiamdia sp Megalonema sp Microglanis sp Bumble bee cat Pimelodella gracilis Slender pimelodella Pimelodella lateristriga Pimelodus maculatus Cunshi Pimelodus ornatus Pimelodella angelica Pimelodus pictus Pseudoplatystoma fasciatum Doncella, Shovelnosed catfish Rhamdia quelen Rhamdia sebae Zungaro zungaro Zungaro CETOPCIDAE (1) Pseudocetopsis plumbeus Whale catfish TRICHOMYCTERIDAE (4) Parasitic catfishes, Pencil catfish Branchioica sp Trichomycterus vittatus Trichomycterus sp Vandellia plazaii Candiru HELOGENIDAE (1) Helogenes marmoratus Marbled catfish CALLICHTHYIDAE (4) Armored Catfish, Corydoras Callichthys callichthys Shirui, Slender Armored Catfish Corydoras semiaquilus Coridora, Sharp nosed corydora Corydoras stenocephalus Coridora, cory Hoplosternum thoracathum Shirui, Port hoplo, Atipa LORICARIIDAE (13) Suckermouth catfish Ancistrus leucostictus Bristle nose Ancistrus sp Bristle nose Aphianatorulus frankei Chaetostoma sp Farlowella sp Hemiodontichthys acipenserinus Farlowella sp. Hypoptoma gulare Hypostomus sp Plecostomus, Sucker catfish Rineloricaria morrowi Whiptail catfish Rineloricaria sp Whiptail catfish Otocinclus vestitus Dwarf sucker catfish Otocinclus sp Sucker catfish Sturisoma nigrirostrum

Nearby oxbow lake biotope | More pictures from Peru | Other biotope profiles
Exploring freshwater fish habitats in the rainforest of Peru


BIOTOPE PICTURES

Reeds along oxbow lake in the Amazon Bladderwort aquatic plant and water lilies growing in natural habitat Oxbow lake Oxbow lake Oxbow lake Bladderwort aquatic plant growing in natural habitat Reeds along oxbow lake in the Amazon Glowlight like tetra (characin) Glowlight like characins Head and tail light tetra, possibly either Moenkhausia sp or Hemigrammus ocellifer Astyanax tetra species Bladderwort aquatic plant growing in natural habitat Floating plants on an oxbow lake in the Amazon Bladderwort aquatic plant and water lilies growing in natural habitat Bladderwort aquatic plant and water lilies growing in natural habitat Bladderwort aquatic plant growing in natural habitat Bladderwort aquatic plant growing in natural habitat Bladderwort aquatic plant and water lilies growing in natural habitat Bladderwort aquatic plant and water lilies growing in natural habitat Bladderwort aquatic plant growing in natural habitat Bladderwort aquatic plant and water lilies growing in natural habitat Bladderwort aquatic plant and water lilies growing in natural habitat Bladderwort aquatic plant and water lilies growing in natural habitat Bladderwort aquatic plant growing in natural habitat Bladderwort aquatic plant growing in natural habitat Bladderwort aquatic plant and water lilies growing in natural habitat Bladderwort aquatic plant and water lilies growing in natural habitat Bladderwort aquatic plant growing in natural habitat Bladderwort aquatic plant and water lilies growing in natural habitat Bladderwort aquatic plant growing in natural habitat Bladderwort aquatic plant growing in natural habitat Oxbow lake Bladderwort aquatic plant growing in natural habitat Bladderwort aquatic plant and water lilies growing in natural habitat Bladderwort aquatic plant and water lilies growing in natural habitat Bladderwort aquatic plant growing in natural habitat Bladderwort and Victoria cruziana water lilies in Oxbow lake Bladderwort aquatic plants in Amazon Oxbow lake

Bladderwort growing near grassy reeds in an Oxbow lake in the Peruvian Amazon Reeds along oxbow lake in the Amazon Clouds over oxbow lake in the Amazon Mesonauta festivus in an Oxbow lake in the Peruvian Amazon Bladderwort aquatic plants in Amazon Oxbow lake Bladderwort and Victoria cruziana water lilies in Oxbow lake Amazon foxtail, aquatic plant, in its wild habitat Bladderwort aquatic plants in Amazon Oxbow lake Bladderwort aquatic plants in Amazon Oxbow lake Bladderwort aquatic plants in Amazon Oxbow lake Bladderwort aquatic plants in Amazon Oxbow lake Bladderwort aquatic plants in Amazon Oxbow lake Bladderwort aquatic plants in Amazon Oxbow lake Bladderwort and Victoria cruziana water lilies in Oxbow lake Bladderwort and Victoria cruziana water lilies in Oxbow lake Bladderwort aquatic plants in Amazon Oxbow lake Bladderwort and Victoria cruziana water lilies in Oxbow lake Bladderwort aquatic plants in Amazon Oxbow lake Bladderwort and Victoria cruziana water lilies in Oxbow lake Amazon foxtail, aquatic plant, in its wild habitat Clouds over oxbow lake in the Amazon Bladderwort and Victoria cruziana water lilies in Oxbow lake Bladderwort aquatic plants in Amazon Oxbow lake Bladderwort aquatic plants in Amazon Oxbow lake Bladderwort aquatic plants in Amazon Oxbow lake Bladderwort aquatic plants in Amazon Oxbow lake Bladderwort aquatic plants in Amazon Oxbow lake Bladderwort aquatic plants in Amazon Oxbow lake Amazon foxtail, aquatic plant, in its natural habitat Bladderwort aquatic plants in Amazon Oxbow lake Bladderwort aquatic plant growing in natural habitat Bladderwort aquatic plant and water lilies growing in natural habitat Bladderwort aquatic plant growing in natural habitat Bladderwort aquatic plant and water lilies growing in natural habitat Bladderwort aquatic plant and water lilies growing in natural habitat Oxbow lake Festive cichlid fish (Mesonauta festivus) in an Oxbow lake in the Peruvian Amazon Bladderwort growing as aquatic plant in an Oxbow lake in the Peruvian Amazon

Bladderwort and Victoria cruziana water lilies in Oxbow lake Bladderwort and Victoria cruziana water lilies in Oxbow lake Bladderwort and Victoria cruziana water lilies in Oxbow lake Bladderwort aquatic plants in Amazon Oxbow lake Bladderwort and Victoria cruziana water lilies in Oxbow lake Serrasalmus piranha species Black piranha (piraña or paña) in Tres Chimbadas oxbow lake Bladderwort growing as aquatic plant in an Oxbow lake in the Peruvian Amazon Bladderwort growing as aquatic plant in an Oxbow lake in the Peruvian Amazon Bladderwort growing as aquatic plant in an Oxbow lake in the Peruvian Amazon Bladderwort growing as aquatic plant in an Oxbow lake in the Peruvian Amazon Festium cichlid fish (Mesonauta festivus) in an Oxbow lake in the Peruvian Amazon Bladderwort growing as aquatic plant in an Oxbow lake in the Peruvian Amazon Bladderwort growing as aquatic plant in an Oxbow lake in the Peruvian Amazon Bladderwort growing as aquatic plant in an Oxbow lake in the Peruvian Amazon Bladderwort growing as aquatic plant in an Oxbow lake in the Peruvian Amazon Bladderwort aquatic plants in Amazon Oxbow lake Bladderwort aquatic plants in Amazon Oxbow lake Amazon foxtail, aquatic plant, in its wild habitat Amazon foxtail, aquatic plant, in its natural habitat Amazon foxtail, aquatic plant, in its natural habitat Bladderwort aquatic plants in Amazon Oxbow lake Bladderwort aquatic plants in Amazon Oxbow lake Bladderwort aquatic plants in Amazon Oxbow lake Oxbow lake with floating Bladderwort and reedy banks Bladderwort aquatic plants in Amazon Oxbow lake Bladderwort and Victoria cruziana water lilies in Oxbow lake Bladderwort aquatic plants in Amazon Oxbow lake Bladderwort aquatic plants in Amazon Oxbow lake Bladderwort aquatic plants in Amazon Oxbow lake Bladderwort aquatic plants in Amazon Oxbow lake Bladderwort aquatic plants in Amazon Oxbow lake Bladderwort aquatic plants in Amazon Oxbow lake Bladderwort aquatic plants in Amazon Oxbow lake Bladderwort aquatic plants in Amazon Oxbow lake Bladderwort aquatic plants in Amazon Oxbow lake Bladderwort aquatic plants in Amazon Oxbow lake

Reference: Goulding M., Cañas C., Barthem R., Forsberg B. and Ortega H. Amazon Headwaters - Rivers,Wildlife,and Conservation in Southeastern Peru. Eco News & Grafica Biblos. Lima, Peru. 2003

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