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his month it is a case of mistaken identity from the Auchenipteridae family and two different genera. There is a species which is very much like Centromochlus musaicus from further south in the lower Rio Nhamundá, in the western Pará, Brazil, Centromochlus orca, previously known in the hobby as Tatia sp. "Ninja". The main differences is that Centromochlus musaicus does not have a white spot/blotch underneath the dorsal fin and has a different pattern on the caudal fin from this species. You can see these subtle differences in the images below.

Centromochlus musaicus

Listed in Soares et al, 2008 and some other publications as Centromochlus musaica, but the former as incertae sedis (of uncertain placement and signifies a taxonomic group difficult to place in the larger taxonomic scheme). Fishbase and Catalog of Fishes follows Ferraris, C.J. Jr. 2003 & 2007 and places it in the Tatia genus as Tatia musaica. Sometimes also named as Tatia musaicus.

Centromochlus orca

Regarding the dubious position of C. musaicus within available genera of Centromochlinae, a reappraisal of phylogenetic relationships within the subfamily is in preparation (LMSS). Based on this ongoing study of centromochlin catfishes, there is some evidence that C. musaicus and C. orca are sister species in a more inclusive Centromochlus clade. In this paper (Sarmento-Soares et al) retains T. musaica (C. musaicus) in Tatia to avoid confusion, but consider Tatia to be a paraphyletic assemblage.

The eyes of Centromochlus are large with a skin over them and a few non catfish aquarists tend to think that they have cloudy eye's and it is a disease, but this is normal for the Auchenipteridae family. The barbels are moderate in length reaching to the end of the dorsal fin and they tend to bend them upwards when looking for food on the water surface. They can also tuck their barbels alongside their cheeks making them nearly invisible. I tend to think that there is a groove in this area where they can lay their barbels in. They possess two pairs of barbels, one pair of mandibular and one pair of maxillary.

Remarks: Just recently (September 2019) a new paper was released by Bárbara B. Calegari et. al. whereas Centromochlus orca was reclassified back to Tatia again.

None

Ninja Tatia

Centromochlinae

South America: Atabapo and Autana River basins in upper Orinoco River drainage, Venezuela/Colombia. Type locality: Río Atuana, Caño Cabeza de Manteco, approximadamente a 12 kms debajo del raudel Pereza, en el pidemonte del tepui Autana, Territorio Federal, Amazonas, Venezuela, 4º47'N, 67º23'W.

5.0cm. (2ins)

22-25°c (71-77°f.)

6.0-7.0.

Examination of material of C. musaicus, including types, revealed that it has features that fit both in Tatia, such as an intermediate caudal peduncle depth, 7.7-12% in SL, and a deeply notched hyomandibula; and Centromochlus, such as elongate maxilla that extends into the maxillary barbel, anterior nuchal plate absent and ventrolateral process of infraorbital 1 forming the anterior border of orbital rim.

Bold pattern of black with three white markings on the belly. The colouration of C. orca resembles that of C. musaicus , leading to the misidentification of Amazonian specimens as C. musaicus. The main differences is that C. musaicus does not have a white spot/blotch underneath the dorsal fin and has a different pattern on the caudal fin from this species.

Whatever the placement of this small driftwood cat it would probably be best kept in the same conditions as Duringlanis perugiae (previously known as Centromochlus perugiae) and would need a planted tank with the lighting not too bright. Give them small pipes, and they do seem to like to hide in the crevices of bogwood as well. They appear to be happier if they can jam themselves in with the use of their pectoral fins. Community tanks are fine for this species although you may find that they will predate on fry from other species, but apart from that they come well recommended but don't expect to see them too often.

The anal fin is the key to the sexual dimorphism of this genus, if you think of the male and female of most livebearer fish (Goodeidae family) and you will not be too far away with this assumption. As you can see above the female has a normal anal fin but the males are modified into a copulatory organ with the first and second ray thickened and longer, it is thought that the male uses this to clasp the female during the spawning embrace.

Centromochlus species are nocturnal; Since they often hide during the daytime during acclimatisation, one has to be careful that they get enough food. However, they also appear during the day for feeding. Feeding of frozen bloodworm which they will come out of hiding to feed on, catfish tablets, daphnia, white worm (sparingly) and any other small worm-like foods.

Anal fin: The median, unpaired, ventrally located fin that lies behind the anus, usually on the posterior half of the fish.
Caudal fin: The tail.
Caudal peduncle: The narrow part of a fish's body to which the caudal or tail fin is attached.
Dorsal fin: The primary rayed fin(s) on top of the body.
Odontodes: Hair - like stuctures on the body.
Papillae: A small fleshy projection, plural papillae.
Pectoral fins: The paired fins just behind the head.

Centromochlus: Centrum = sting; mochlus = lever, from ancient Greek "lever arm", referring to the pectoral spines which can be a locked by a special mechanism.

Ferraris, C.J. Jr., 2007. Checklist of catfishes, recent and fossil (Osteichthyes: Siluriformes), and catalogue of siluriform primary types. Zootaxa 1418:1-628.
Grant, S., 2015. Four new subgenera of Centromochlus Kner, 1858 with comments on the boundaries of some related genera (Siluriformes: Auchenipteridae: Centromochlinae). Ichthyofile No 3. pp, 1-16.
Sarmento-Soares, Luisa Maria; Martins-Pinheiro, Ronaldo Fernando A systematic revision of  Tatia (Siluriformes: Auchenipteridae: Centromochlinae) Neotropical Ichthyology, 6(3):495- 542, 2008.
ScotCat Factsheet no. 60. June 2001.

Photo Credits

Top image: (C. musaicus) © Flair Wang
Bottom Image: (C. orca) © Yann Fulliquet