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Liosomadoras oncinus  (Jardine, 1841)

ur first factsheet of 2005 takes us back to the South American continent and to a member of the Auchenipteridae family
which was discovered 164 years ago in Brazil by R. H. Schomburgk in 1841, and this beautiful catfish has had a checkered history ever since.

Liosomadoras oncinus


Schomburgk named it Arius oncinus after the species name of the Jaguar Cat (Panthera onca) due to its body pattern resembling this cat of the South American rain forests. In 1940, Fowler described a new species from Peru, Liosomadorus morrowi, and placed it in the Doradidae family even although it did not have the bony scutes that this family possess, but it had the spiny humeral process of this family.

Onwards to 1978 and an article with illustrations appeared in the TFH magazine by Martin Brittan and it alerted the Ichthyologist, Mees, who subsequently published a paper on this catfish. Mees noted that the fish in the article, which was mooted as a Centromochlus species, looked very like the original description by Schomburgk. He obtained specimens form Brittan and also the type specimen of L. morrowi and concluded, incorrectly, that they were one and the same fish and placed it in the Doradidae family. It was not until 1994 that these two species were considered as separate and they were placed in the Auchenipteridae family.

Liosomadoras oncinus

Stamp depicting the original colour plate of Liosomadoras oncinus

This is indeed a beautifully
marked catfish but in the aquarium you may not see too much of its beauty as it can be crepuscular in nature and will need hiding places to make it feel more secure and happy in its surroundings.

Liosomadorus morrowi

Liosomadorus morrowi

Above is Liosomadorus morrowi, the Black Jaguar Catfish. I was given this fish by a friend who had bought it as a Jaguar Cat and did not know what it was. You may find the common name of the Black Jaguar Catfish misleading from this picture, but this photo was taken on the show bench and it had lost the dark markings that you will find when it is settled in your tank set up. The parameters given for L.oncinus will be the same for L morrowi.


Body short and compact with a compressed caudal peduncle. Head, large and broad, its width at the clavicles greater than its length. The long humeral extension has small spines and the barbels are thin and filamentous without branches. Dorsal spine has teeth on anterior and posterior edges. Pectoral spines have outer and inner margins strongly denticulated. Adipose fin is the same length as the anal fin, ventral fins short and positioned nearer the anal fin than the pectoral fin base. Caudal fin emarginate.

Yellow blotches on a brown body bordered on each side of the distinct lateral line. Fins spotted.

Can be kept in a community tank but may eat very small fish at night such as the fry of livebearers, but basically a good addition to the larger tank set up.

There are no known reported aquarium spawning's of this catfish but can be sexed due to the thickening of the anterior of the anal fin, as is the norm in this family, akin to the anal fins of the males of the Goodiae family of livebearers.

Will take most prepared foods such as frozen bloodworm, tablet and flake food. Better to feed at night after lights out, but once settled in tank will forage for food in low light conditions.

Liosomadoras: From the Greek leios, meaning smooth; soma; meaning body and Doras (a genus of doradid catfishes); in reference to the lack of bony plates on the body (when the genus was described as a doradid).
oncinus: Named after the Jaguar cat, Panthera onca, because of its markings.

Finley, Lee, Catfish Corner, The Jaguar Catfish, Tropical Fish Hobbyist; Aug.1997 p104-108
Burgess, W.E., 1989 An Atlas of Freshwater and Marine catfishes: a preliminary survey of the Siluriformes. T.F.H. Publications, Neptune City, New Jersey

Photo Credits
Top:        © Ian Fuller @CorydorasWorld

Bottom:  © Julian Dignall @  
Planet Catfish
Factsheet 103

Arius oncina, Arius oncinus, Liosomadorus morrowi
Common Name:
Jaguar Catfish
 Brazil Brazil, Negro and Branco River basins. Type locality: Padauiri River.
17.5cm. (7ins)
20-24°c (67-75°f.)
5.5 - 6.8
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                                                                                                Factsheet 103 = updated December 30, 2004, © ScotCat 1997-2019 Go to Top