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Library > Cichlids > General Articles > Taxonomy of Cichlids > Sub Family Astronotinae > Genera Astronotus > Astronotus crassipinnis
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Species Astronotus crassipinnis


Scientific classification
Kingdom : Animalia
Phylum : Chordata
Class : Actinopterygii
Order : Perciformes
Suborder : Labroidei
Family : Cichlidae
Sub Family : Astronotinae
Genus   Astronotus
Scientific Name : Astronotus crassipinnis
Common Name :
Geo Origin : AMERICA, South America, Near Rio Paraguay, Villa Maria and Caisara, Rio Guaporé close to Matogrosso, Rio Negro, and Rio Branco    
Diet : Carnivore
Gender Differences : Mono morphic
Breeding : Substrate Spawner
Temperament : Aggressive
Con specific Temperament : Aggressive
Standard Length : 9"
Total Length : 11"
Water Hardness: Soft, ph range: 6-7, dH range: 5-19
Difficulty ;


Astronotus crassipinnis is a close relative to the famous Oscar fish Astronotus ocellatus. The name crassipinnis is derived from the Latin words crassus and pinna which means "fat" and "fish" respectively.


Crassipinnis are member of Genus Astronotus which is placed in subfamily Astronotinae.

Crassipinnis was scientifically described by Heckel in 1840 and given the name Acara crassipinnis, but is now considered a member of the genus Astronotus.



Astronotus crassipinnis reached a standard length of 9" , compared to 18" for Astronotus ocellatus
Both species are known to exhibit a variable bar pattern, but Crassipinnis is overall darker than Oscar and its anterior most light vertical bar is located more anterior than on an Oscar.
The area where one would find the first light bar on an Oscar is instead decorated with two more or less well-separated dark vertical bars on a Crassipinnis. In addition to this, Crassipinnis does not have the two eye-spots along the base of its dorsal fin that adorns the western Amazonian Oscar.

Distribution & Habitat:

A. crassipinnis is found are Rio Paraguay, Villa Maria and Caisara, Rio Guaporé close to Matogrosso, Rio Negro, and Rio Branco.

The species inhabits the Bolivian parts of the Amazon and the Rio Madre de Dios drainage in Peru, plus the Rio Paraná basin in the Rio Paraguay drainage in Paraguay and Brazil.

Sexual Dimorphism

A. crassipinnis is monomorphic. i.e male and females are alike.



A.crassipinnis is carnivorous by nature and may be fed prepared fish food designed for large carnivorous fish, crayfish, worms, and insects (such as flies or grasshoppers).

Feeding live foods may increase the rate of growth but also may cause endoparasites.

Poultry and/or mammalian flesh, including beef heart, should not be fed long term as these fatty foods will contribute to fatty liver disease.

Live feeder fish can be given, but fish such as goldfish and rosy red feeder minnows should not be fed.
These contain an enzyme (thiaminase) within their flesh which binds vitamin B1, leading to deficiency.




Tank Size:

Compared to the popular Oscar, very little is known about Crassipinnis and the information that do exist is often vague or conflicting.. It is still rare within the hobby and seldom exported from South America, and the regions in which it lives are far from thoroughly explored.

However , it is important to have or be prepared to eventually get a large aquarium.
It is true that the largest scientifically measured Crassipinnis was 24 cm / 9.4 in, but this doesn't mean that it must be impossible for this species to grow any larger there might be even larger specimens lurking in South America unknown to science

Since we still know so little about Astronotus crassipinnis it is best to play it safe and assume that it might one day become as large as an Oscar. Also keep in mind that the comfortable life in a well-kept aquarium can make some species grow much larger than they would in the wild.


Since Crassipinnis is quite a messy eater and produces a lot of waste, powerful mechanical and biological filtration is typically necessary even in large and under-stocked aquariums.
Even with powerful filtration, it is important to keep an eye on the water quality.

Substrate & Decor:

As the fish lives in South America the layout of aquarium should mimic that environment.
Mangrove roots or similar is a good idea since roots will provide your fish with dark and sheltered spots for resting.
Live plants floating on the surface will also be highly appreciated and make your fish feel more at home. Planted plants can also be used, but your Crassipinnis may uproot them so ideally go for robust species.

Water parameters:

Crassipinnis needs soft water and acidic water with a pH of 6.5-6.9.
The species live in tropical South American rivers and the recommended water temperature in the aquarium is 21-28°C / 70-83°F
If you decide to keep the water in the upper part of the range, don't forget that warm water holds less oxygen than cooler water.
If your filtration system isn't enough to keep the oxygen level up you can get one or several air stone


A. crassipinnis has been observed, in times of danger, to store brood in its mouth, possibly for protection, in a manner reminiscent of mouth brooding Geophaginae cichlids

This behavior, however, has not yet been observed in A. ocellatus.


  Sandeep Raghuvanshi
Picture Credits   Wikipdeia and other sources which have releases under GNU, unless specifically credited

Froese, R. and D. Pauly. Editors. 2011.FishBase. World Wide Web electronic publication., ( 10/2013 )

Kullander, S.O., 2003. Cichlidae (Cichlids). p. 605-654. In R.E. Reis, S.O. Kullander and C.J. Ferraris, Jr. (eds.) Checklist of the Freshwater Fishes of South and Central America. Porto Alegre: EDIPUCRS, Brasil