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Microglanis poecilus Eigenmann, 1912

here are now as of January 2019, 24 species of Microglanis from the Pseudopimelodidae family, the last two named in 2016, Microglanis nigrolineatus and Microglanis xerente. We concentrate this month on a species well known in the hobby but only now becoming more readily available, the Dwarf marbled catfish, Microglanis poecilis.

Microglanis poecilus
Microglanis poecilus



The most common Microglanis species that you will encounter will be M. iheringi which is exported more often than our factsheet of the month due to the accessibility of each species. In the last few years more aquarists are collecting in the rivers of French Guiana, Suriname and Guyana and so this catfish is becoming more readily available to the hobbyist although it is still a rare species to be seen in your local fish shop.


There can be confusion between another three species of the same genera,
Microglanis iheringi, M. secundus and M. parahybae. There are diferences in colour patterns, especially on the caudal peduncle and caudal fin areas.



Microglanis poecilus - caudal view


Microglanis poecilus - caudal view



The line drawings below may help you to identify your Microglanis but being able to see your species in your tank to do this is another matter entirely as they are very secretive as you can go months without spotting them, unless you can view them with the lights out at night when they come out for their forays.



M. poecilus
M. poecilus
M. iheringi
M. iheringi
M. parahybae
M. parahybae
M. secundus
M. secundus



Essequibo River basin


Essequibo River basin

To sum up, a very nice looking pim, while being very nocturnal, but being able to see them on the odd occasion makes up for the weeks that you thought you had lost it, and so a nice addition to a medium sized community tank. It would be better to purchase a few of this species instead of a single individual as they will be happier with conspecifics.

Remarks: in some publications the Standard Length is documented as 3.5cm.



Premaxillary dental plate with rounded lateral margin. The caudal fin is somewhat variable, usually scalloped with rounded (or at least not very sharp) lobes, the upper one the larger. Lateral line not complete. Maxillary teeth without backward projection. Pectoral fin with i,5 rays; tip of pectoral spine pointed.

Dark brown markings on a light brown background. The pale band across the nape is irregular, running zigzag and in a few specimens it is actually interrupted, the dark area on the head and predorsal region being in contact across it. The dark area below the dorsal fin is a peculiar four cornered shape when the fish is viewed from above. A dark area on the adipose fin and just below, with a light patch at the origin of the adipose fin. The dark band across the caudal peduncle is always more or less triangular in shape. The dark markings on the body are enhanced by the fact that just around them the background is paler than elsewhere on the body, almost white instead of light brown. Dorsal fin with a dark bar about one third halfway up, caudal fin with a dark vertical bar about one third from end, all the fins are minutely spotted.

Aquarium Care

Hiding places such as rockwork, plants and or wood will benefit this species and help, along with regular water changes, to keep it happy in its surroundings.



A good addition to the medium sized community tank, and will not harm the occupants unless they are small enough to fit into its mouth such as newly born fry and young fish. If you keep livebearers such as Guppies and Platies in with them you will very rarely be overrun with fry as the Dwarf marbled catfish will promptly finish them off on its night time prowls.

Not recorded but there is a report on the breeding of Microglanis iheringi on the factsheet of April 2004.

Sexual differences
Males are slimmer than females.


Can be fed a varied diet of tablet food, pellets, worm foods and frozen food such as bloodworm.

Glossary of Terms

Caudal fin: The tail.
Dorsal fin:
The primary rayed fin(s) on top of the body

Lateral line: A sensory line, along the sides of the body.
Maxillary teeth: Pertaining to the upper jaw.
Pectoral fins: The paired fins just behind the head.
Adipose fin: Fleshy finlike projection without rays, behind the rayed dorsal fin.
Caudal peduncle: The narrow part of a fish's body to which the caudal or tail fin is attached.


Microglanis: Greek, kranion = skull + Greek, glanis = the name of a kind of fish.
poecilus: From the Greek, poikilos = variecoloured, pied, mottled, spotted.



By Kmusser - Own work using Digital Chart of the World and GTOPO data., CC BY-SA 3.0, https://commons.wikimedia.org/w/index.php?curid=4766156
Catfish Association of Great Britain: Information Book 4. 1978. 23p.
Ferraris, C.J. Jr., 2007. Checklist of catfishes, recent and fossil (Osteichthyes: Siluriformes), and catalogue of siluriform primary types. Zootaxa 1418:1-628.
Mol, H.A. Jan, The Freshwater Fishes of Suriname. BRILL, Leiden Boston, 2012. 889 p.
Sleen, van der Peter and Albert, S. James; Field guide of the Amazon, Orinoco & Guianas. Princeton University Press, Princeton and Oxford. 2018.

Photo Credits

©  Steven Grant: @ Catfishes of the World

Factsheet 272

Common Name:
Dwarf marbled catfish


South America: Essequibo River basin and rivers of French Guiana. Type locality: Below Packeoo Falls, British Guiana.
7.0cm. (3¾ins)
21 -25°C (69-77°F)
6.0 -7.5.
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                                                                                                            Factsheet 272 = updated January 30, 2019 , © ScotCat 1997-2019  Go to Top