Amazon oxbow lake biotope aquarium, a freshwater habitat in Peru

Amazon oxbow lake biotope aquarium, a freshwater habitat in Peru


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.


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

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.

Compiled by Mario Napravnik

Acestrocephalus boehlkei
Acestrorrhynchus lacustrisCachoro, Pike characin
Aphyocharax pusillusBloodfin
Aphyocharax alburnusBloodfin
Aphyocheirodon sp
Astyanaclnus multidens
Aslyanax abramis
Astyanax anteroides
Aslyanax bimaculatus
Astyanax fasciatusTwo spotted Astianax Silvery tetra
Astyanax maxiumus
Bario steindachneri Blotch tailed bario
Brachichalcinus copei
Brycon erythropterumSabalo cola roja
Bryconacydnus ellisi
Bryconamencus pachacuti
Bryconops melanurusTail light tetra
Characidium fasciatus
Charax gibbosusGlass Headstander
Charax tectiferGlass Headstander
Cheirodon fugitiva
Cheirodon piaba
Cheirodon ait. notomelas
Creagrutus affinis
Creagrutus anary
Creagrutus beni
Ctenobrycon hauxwellianus
Galeocharax gulo
Gephyrocharax sp
Gymnocorymbus temetziBlack widow, Skirt Tetra
Gymnocorymbus thayeri
Hemibrycon jelskii
Hemibrycon jabonero
Hemigrammus lunatus
Hemigrammus ocelliferHead and tail light tetra
Hemmigrammus sp
Holoshestes heterodon
Hydroyicus sconberoides
Hyphessobrycon agulhaRed 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 dichrouraSpot tailed Moenkhausia
Moenkhausia jamesii
Moenkhausia oligolepisGlass tetra
Moralesia tectifera
Myleus rubripinnis
Othonocheirodus lethostigmus
Paragoniates alburnus
Phenacogaster pectinatus
Piabina beni
Piaractus brachyponusPacu
Pigocentrus nattereriRed piranha
Poptella compresa
Prionobrama filigeraGlass bloodfin
Raphiodon vulpinusChambira
Rhynobrycon negrensis
Roeboides affinisGlass characin
Roeboides myersiiGlass characin
Salminus aflinis
Serrasalmus humeralisPiranha
Serrasalmus rhombeusBlack piranha, Spotted piranha
Serrasalmus spilopleuraFire mouth piranha
Tetragonopterus argenteus
Triportheus albusSardina, sapanama
Triportheus angulatusSardina, Narrow Hatchetfish, sapanama
Tyttocharax spBristly mouthed tetra
Carnegiella schereriHatchet lish
Carnegiella myersiiMyersi hatchetfish
Thoracocharax stellatusSilver hatchetfish
ERYTHRINIDAE (3)Trahlras, huasacos
Erythrynus eryihrinusShort finned trahira
Hoplerytrhinus unitaeniatusTrahiras, huasacos
Hoplias malabaricusFasaco, Tiger fish, trahira
LEBIASINIDAE (1)Pyrrhulina
Pyrrhulina vittataBanded pyrrhulina
Prochilodus mariae
Prochilodus nigricans
Curimata sp
Cyphocharax sp
Steindachnerina dobula
Steindachnerina guentheri
Steindachnerina hypostoma
ANOSTOMIDAE (3)Leporinus
Leporinus fridericiFriderici leporinus
Leporinus striatusStriped leporinus
Leporinus yophoru
GYMNOTIDAE (2)Knife fish
Gymnotus carapoBanded Knife fish
Gymnotus coatesiKnife fish
Stemopygus macrurusGhost Knife fish
Sternopygus virescensKnife fish
HYPOPOMIDAE (2)Knife fish
Hypopomus muelleriKnife fish
Hypopomus spSpoted knife fish
Electrophous electricusElectric eel
Gymnorhamphichthys sp
Potamotrygon motoroFreshwater Stingray
Anchoviella carrikeri
Anchoviella guianensis
Lycengraulis batessi
Astroblepus sp
Rivulus urophtalmos
Pachyurus schomburgkiiAmazon croaker
Synbranchus marmoratusAtinga, Marbled Eel
Aequidens tetramerusSaddle Cichlid
Apistogramma luelingi
Apistogramma urteagai
Bujurquina cordemadi
Bujurquina tambopataeTambopata Flag Cichlid
Cichlasoma boliviense
Crenicichla semicinctaPike Cichlid
Mesonauta festivumFestive Cichlid
Satanoperca jurupariJurupari, Eartheater, Demon eartheater
DORADIDAE (1)Talking catfishes
Trachydora nattereriTalking catfish
AUCHENIPTERIDAE(2)Driftwood catfishes
Auchenipterus nuchalis
Trachelyopterus sp
ASPREDINIDAE (1)Banjo catfish
Dysichtys spSmooth banjo catfish
PIMELODIDAE (15)Antenna catfishes
Brachypatystoma spZungaro, Gilded catfish
Brachypatystoma filamentosumSalton, Gilded catfish
Brachypatystoma flavicansDorado, Gilded catfish
Cheirocerus eques
Goslinea platinemaMota flemosa
Heptapterus sp
Impartinnis sp
Hanhortiamdia sp
Megalonema sp
Microglanis spBumble bee cat
Pimelodella gracilisSlender pimelodella
Pimelodella lateristriga
Pimelodus maculatusCunshi
Pimelodus ornatusPimelodella angelica
Pimelodus pictus
Pseudoplatystoma fasciatumDoncella, Shovelnosed catfish
Rhamdia quelen
Rhamdia sebae
Zungaro zungaroZungaro
Pseudocetopsis plumbeusWhale catfish
TRICHOMYCTERIDAE (4)Parasitic catfishes, Pencil catfish
Branchioica sp
Trichomycterus vittatus
Trichomycterus sp
Vandellia plazaiiCandiru
Helogenes marmoratusMarbled catfish
CALLICHTHYIDAE (4)Armored Catfish, Corydoras
Callichthys callichthysShirui, Slender Armored Catfish
Corydoras semiaquilusCoridora, Sharp nosed corydora
Corydoras stenocephalusCoridora, cory
Hoplosternum thoracathumShirui, Port hoplo, Atipa
LORICARIIDAE (13)Suckermouth catfish
Ancistrus leucostictusBristle nose
Ancistrus spBristle nose
Aphianatorulus frankei
Chaetostoma sp
Farlowella sp
Hemiodontichthys acipenserinus
Farlowella sp.
Hypoptoma gulare
Hypostomus spPlecostomus, Sucker catfish
Rineloricaria morrowiWhiptail catfish
Rineloricaria spWhiptail catfish
Otocinclus vestitusDwarf sucker catfish
Otocinclus spSucker catfish
Sturisoma nigrirostrum

Aquarium Gone Wild Peru lists the following fish as being locally available in the Madre de Dios region.

Acanthodoras spinosissimus
Ancistrus sp.
Anduzedoras sp.
Aphanatorulus sp.
Aphanatorulus unicolor
Astroblepus sp.
Baryancistrus sp.
Brochis cf. britski
Brochis splendens
Bunocephalus sp.
Callichthys callichthys
Cetopsis coecuitens
Cochliodon sp.
Corydoras aeneus
Corydoras cf. aeneus
Corydoras cf. napoensis
Corydoras cf. trilineatus
Corydoras elegans
Corydoras eques
Corydoras latus
Corydoras weitzmani
Crossloricaria sp.
Crossloricaris bawahja
Dysichthys sp.
Entomocorus sp.
Farlowella sp.
Glyptoperichthys sp.
Helogenes marmoratus
Hemicetopsis sp.
Hemiodontichthys acipenserinus
Holplosternum litoralle
Hoplosternum thoracatum
Hypoptopoma sp.
Hypostumus sp.
Imparfinis sp.
Lamontichthys sp.
Loricarichthys sp.
Loricariidae sp.
Microglanis sp.
Nannoptopma sternoptychum
Otocinclus sp.
Otocinclus sp. cf. vestitus
Panaque sp.
Panaquolus sp.
Parauchenipterus galeatus
Parauchenipterus sp.
Pimelodella dorseyi
Pimelodella linami
Pimelodus ornatus
Pimelodus sp.
Pinirampus pinirunpu
Platystomatichthys sturio
Pseudopimelodus ranius
Pseudoplatystoma tigrinum
Pseudoplatystoma fasciatum
Psuedohemidon sp.
Rineloricaria lanceolata
Rineloricaria sp.
Suurisoma sp.
Tatia sp.
Trichomycterus sp.
Acaronia nassa
Aequidens tetramerus
Apistogramma cf. luelingi
Apistogramma cf. urtegai
Apistogramma rubrolineata
Apistogramma sp.
Apistogramma urtegai
Astronatus crassipinnis
Bujurquina sp.
Cichlasoma boliviense
Crenicichla sp.
Mesonauta festivus
Satanoperca jurupari
Satanoperca sp.
Acestrorhynchus falcatus
Anostomus anostomus
Anostomus sp.
Aphyocharax alburnus
Aphyocharax detatus
Aphyocharax pusillus
Astyanax bimaculatus
Boehlkea fredcochui
Bryconops melanurus
Carnegiella myersii
Carnegilla cf. strigata
Carnegilla sp.
Characidium fasciatum
Chilodus sp.
Chirodon kreggi
Ctenobrycon spirlurus
Exoden paradoxus
Hemigrammus elegans
Hemigrammus rodwayi
Hemigrammus sp.
Hyphessobrycon nigricinctus
Hyphessobrycon sp.
Hyphessobrycon stegemani
Hyphessobrycon vilmae
Leporinus desmotes
Leporinus friderici
Leporinus yophorus
Mimigoniates microlepis
Mimigoniates sp.
Monkhausia intermedia
Monkhausia santaefilonenae
Monkhausia sp.
Myleus sp.
Mylossoma aureum
Nannostomus marginatus
Paradon affinis
Phenacogaster sp.
Piaractus brachypomus
Prionobrama filigera
Pristella sp.
Pyrrhulina sp.
Pyrrhulina vittata
Roeboides affinis
Roeboides sp.
Serrasalmus cf. rhombeus
Serrasalmus sp.
Tetragonopterus sp.
Thorachocarax stellatus
Tyttocharax tambopatensis
Aphyolebias rubrocaudatus
Moema quiii
Rivulus beniensis
Rivulus christinae
Rivulus sp. Alta Chonta
Rivulus sp. Jayave
Rivulus sp. Maniri
Rivulus sp. Manuripe
Rivulus sp. Nusiniscato
Rivulus sp. Palcomayo
Rivulus sp. Palmera
Rivulus sp. Quimiri
Rivulus sp. San Gabon
Rivulus sp. Saniaca
Rivulus sp. Santa Rita
Rivulus sp. Vitobamba
Eigenmannia sp.
Eremophilus candidos
Erthrinus sp.
Gymnorhamphichthys rondoni
Gymnotus carapo
Gymnotus sp.
Hoplerythrinus sp.
Potamorrhaphis guianensis
Potamotrygon hystrix
Potamotrygon motoro
Potamotrygon sp.
Potamotrygon sp. cf.castexi
Rhamphichtys sp.
Steatogenys sp.
Synbranchus marmoratus
Trinectes maculatus

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

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