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Pterodoras granulosus  (Valenciennes, 1821)    

his months factsheet, April 2016, is concentrating on the Doradidae family or commonly known as the "talking cats" due to the noise they make when removed from the water. Confused sometimes with the Auchenipteridae family ( Wood cats ) but they possess a row of scutes along their sides which is characteristic of this group. Our subject is the "Granulated catfish" Pterodoras granulosus which is rather on the plain side but can have some interesting shades of brown and olive depending on what location they are captured in and their age. In their natural habitat they will form small groups and feed mainly on mollusc's and the fruits/nuts of the palm tree, Astrocaryum javary.




Pterodoras granulosus


They can sometimes be identified by their small eyes high on their head and the forked tail. In common with most of this family they are nocturnal so hiding places in the aquarium are essential for their well being. As this is quite a sizeable "Dorad", a large tank or heated pond at least 7'0 long with a footprint of at least 4ft. in width so that it can turn round would be beneficial. This is not a species for your usual community tank as an adult size of 36ins (90cm) is a veritable lump of catfish.




Chris Ralph in Peru 2000


I along with other U.K. aquarists (see articles) visited Peru in 2000 and the image above portrays author and aquarist Chris Ralph with his catchment of a juvenile Pterodoras granulosus in the wild. In specimens collected in the Amazon River during a period of low water, the stomachs contained large amounts of plant material and the intestine corresponded on average 215% of the length standard (Maple and Sanchez, 2002).


This species was captured in lagoons from overflowing and to the main channel of the Amazon River. They can survive for hours out of water provided that their skin stays wet. Is is also very common to find them alive in the local markets.



Head is wider than long. They have 3 pairs of barbels and posess small eyes. The humeral process is relatively short. 25 to 30 scutes adorn its sides. The adipose fin extends and forms a keel. The caudal fin is strongly forked.

The colouration of the body varies with age. Juveniles are brown clear, with lots of dark spots of the size of the eye and distributed irregularly throughout the body and fins. Adults lose this dot pattern and acquire a uniform tone green olive.

Aquarium Care

As with most "Dorads" they are quite adaptive to water parameters but there is a question mark on p.H. values above 7.5 as there are reports ( Baensch, H.A. and R. Riehl, 1985) that this high p.H. can cause eye and skin cloudiness. Provide hiding places such as pipes large enough for these large "Dorads" to squeeze into and a tank with subdued lighting.



Can be housed with large cichlids, catfish and larger characins. Peaceful catfish for its size but could mistake smaller species as food on its night time forays.

Not reported

Sexual Differences

Not known but presumably the female would have a wider girth.


In nature they feed on snails, water plants and fruits. The usual aquarium fare will suffice. Trying different fruits would be a good project for this species

Glossary of Terms

Scutes: Bony covering.
Active at night
Whisker-like structure on the heads of most catfish.

Humeral process: Bony extension of the pectoral girdle.

Adipose fin: Fleshy finlike projection without rays, behind the rayed dorsal fin.
Caudall fin: The tail.



Pterodoras: Greek, pteron = wing, fin + Greek, doras = skin.
Named after the nature of skin with granules.

Baensch, H.A. and R. Riehl, 1985. Aquarien atlas. Band 2. Mergus, Verlag für Natur-und Heimtierkunde GmbH, Melle, Germany. 1216 p.
Conservación Internacional; seris de Guías Tropicales De Campo. Pecos del medio Amazonas Región de Leticia. 546 p.

Photo Credits

© Wolfgang Ros @ Catfish and more

Bottom: © Chris Ralph




Factsheet 238

Doras granulosus, Doras maculatus, Doras murica, Doras lentiginosus, Pterodoras lentiginosus, Silurus armatus, S. duodecimradiatus, Parapterodoras paranensis  
Common Name:
Granulated catfish
South America: Amazon and Paraná River basins and coastal drainages in Guyana and Surinam.
90cm. (36ins)
20-24°C (67-75°F)
6.0 - 7.0.
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