''Oxydoras niger'', the ripsaw catfish or cuiu cuiu, is a species of thorny catfish native to the

Amazon Amazon most often refers to: * Amazons, a tribe of female warriors in Greek mythology * Amazon rainforest, a rainforest covering most of the Amazon basin * Amazon River, in South America * Amazon (company), an American multinational technology c ...

, Essequibo and São Francisco basins in

Bolivia , image_flag = Bandera de Bolivia (Estado).svg , flag_alt = Horizontal tricolor (red, yellow, and green from top to bottom) with the coat of arms of Bolivia in the center , flag_alt2 = 7 × 7 square p ...

Brazil Brazil ( pt, Brasil; ), officially the Federative Republic of Brazil (Portuguese: ), is the largest country in both South America and Latin America. At and with over 217 million people, Brazil is the world's fifth-largest country by area ...

Colombia Colombia (, ; ), officially the Republic of Colombia, is a country in South America with insular regions in North America—near Nicaragua's Caribbean coast—as well as in the Pacific Ocean. The Colombian mainland is bordered by the Car ...

Ecuador Ecuador ( ; ; Quechua: ''Ikwayur''; Shuar: ''Ecuador'' or ''Ekuatur''), officially the Republic of Ecuador ( es, República del Ecuador, which literally translates as "Republic of the Equator"; Quechua: ''Ikwadur Ripuwlika''; Shuar: ''Eku ...

Guyana Guyana ( or ), officially the Cooperative Republic of Guyana, is a country on the northern mainland of South America. Guyana is an indigenous word which means "Land of Many Waters". The capital city is Georgetown. Guyana is bordered by the ...

Peru , image_flag = Flag of Peru.svg , image_coat = Escudo nacional del Perú.svg , other_symbol = Great Seal of the State , other_symbol_type = Seal (emblem), National seal , national_motto = "Fi ...

and

Venezuela Venezuela (; ), officially the Bolivarian Republic of Venezuela ( es, link=no, República Bolivariana de Venezuela), is a country on the northern coast of South America, consisting of a continental landmass and many islands and islets in th ...

. This species grows to a length of SL and weights up to . This species is a minor component of local

commercial fisheries Commercial fishing is the activity of catching fish and other seafood for commercial profit, mostly from wild fisheries. It provides a large quantity of food to many countries around the world, but those who practice it as an industry must often ...

. It has lateral thorns that can damage any potential predator or handler. It feeds by shifting through sand and detecting eatable parts with the taste receptors in the roof and floor of its mouth.

Ecology

''Oxydoras niger'' occurs over mud in streams and lakes. It is known from temperatures ranging from 24–29.8 °C (75–85.6 °F), pH range of 5–9, and an

alkalinity Alkalinity (from ar, القلوي, al-qaly, lit=ashes of the saltwort) is the capacity of water to resist acidification. It should not be confused with basicity, which is an absolute measurement on the pH scale. Alkalinity is the strength of ...

range of 42–142. It is known to form schools. This species feeds on

detritus In biology, detritus () is dead particulate organic material, as distinguished from dissolved organic material. Detritus typically includes the bodies or fragments of bodies of dead organisms, and fecal material. Detritus typically hosts commun ...

chironomid The Chironomidae (informally known as chironomids, nonbiting midges, or lake flies) comprise a family of nematoceran flies with a global distribution. They are closely related to the Ceratopogonidae, Simuliidae, and Thaumaleidae. Many species ...

and ephemeropteran

larva A larva (; plural larvae ) is a distinct juvenile form many animals undergo before metamorphosis into adults. Animals with indirect development such as insects, amphibians, or cnidarians typically have a larval phase of their life cycle. The ...

e, and crustaceans.

In the aquarium

''Oxydoras niger'' is a popular

aquarium An aquarium (plural: ''aquariums'' or ''aquaria'') is a vivarium of any size having at least one transparent side in which aquatic plants or animals are kept and displayed. Fishkeepers use aquaria to keep fish, invertebrates, amphibians, aq ...

fish species. In the hobby, it goes by many names, including black talking catfish, razorback catfish, mother of snails catfish, ripsaw catfish and black doradid. This species grows to a large size and are often bought by unsuspecting aquarists when small. They will rapidly outgrow smaller tanks, so the aquarium should be as large as possible. ''O. niger'' is especially light shy and should be provided with sheltered areas to hide. Although these fish are peaceful, very small tankmates are still at risk of being eaten. This species readily accepts prepared foods. ''O. niger'' has not been bred under aquarium conditions.

References

Doradidae Fish of Bolivia Freshwater fish of Brazil Freshwater fish of Colombia Freshwater fish of Ecuador Freshwater fish of Peru Fish of the Amazon basin Fish described in 1821 Taxa named by Achille Valenciennes {{Doradidae-stub