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his is one of two species in the Dianema genus which we covered way back 11 years ago with Dianema urostriatum in Factsheet no. 29, in November 1998, and basically completes the set!.

Dianema longibarbis

As catfish species go you could say that this is a plain Jane, but more than makes up for it with its easy to keep and friendly demeanor.

You can see why it got its common name of the "Porthole Catfish" as the sides of the body are adorned with lines of spots akin to your normal everyday ocean going liner. The spots on the head are that bit smaller. The top picture shows an adult specimen while the bottom image shows a younger specimen.

Dianema longibarbis

Alongside D. urostriatum they are very difficult to induce to spawn which is a bit of a mystery as their counterparts in the Hoplosternum/Megalechis genera are quite easy by contrast. They are very easy to keep in a normal community aquarium as they will not bother any other tankmates and as with most catfish they will need some form of shelter such as plants and or driftwood/pipework/stones.

Porthole catfish

Callichthys adspersus, Decapogon adsperus

Callichthyinae

South America: Brazil; Peru, Rio Ambiyacu.

9.0cm (3½ins)

22-26°C (71-79°F)

Dianema is diagnosed by the first infraorbital bone not articulating with the lateral ethmoid; metapterygoid with an interdigitated suture with the quadrate; and lower lip with two small barbels on each side. Caudal fin slightly forked.

This is a peaceful midwater to bottom swimmer that will do better if kept in a group of at least 4 as individuals on their own tend to sulk and never seem to progress too well. Try to resist placing them in an aquarium with aggressive species such as some Cichlids, they will do better with the usual community type fish and of course along with Corydoras sp.

This fish has proved a challenge for quite a few catfish enthusiasts over the years. There has been unconfirmed reports of breeding triumphs but no documentation as yet to prove this theory. It is reported to be a bubblenest breeder just like its cousins in the Hoplo/Megalechis/Lepthoplosternum-complex. Try to reduce the water level and increase the temperature to 28°C (82°F) to initiate breeding.

Males have marginally thicker pectoral spines and are more slender then the females.

Will take most aquarium fare such as good quality flake, tablet food and frozen food such as bloodworm.

Ethmoid: Unpaired skull bone on the anterior part of the neurocranium forming part of the nasal cavity and located above the vomer.
Infraorbital: The area below the eye. Name applied to the first six circumorbital bones: suborbital 1 (lachrymal or preorbital), suborbital 2 (jugal), suborbital 3 (true postorbital), suborbitals 4 and 5, and suborbital 6 (dermosphenotic). Also called infraorbital bones. Associated with the infraorbital lateral line. Sometimes reserved for a chain of small bones below the infraorbitals and unrelated to the infraorbital sensory canal, e.g. in palaeoniscoids, usually absent in advanced fishes.
Pectoral fins: The paired fins just behind the head.
Quadrate: A paired, triangular, deep, endochondral bone on which the mandible hinges, connecting the lower jaw to the palatine and hyoid arches. During evolution becomes the incus bone of the inner ear of mammals.
Suture: Line of juncture of two parts; ragged line of union between two bones cemented with connective tissue.
Supraoccipital: Unpaired bone at the back of the skull, usually with a crest.

Dianema: Dia = through; nema = thread. The gender of this name is neuter, not feminine as usually thought.
longibarbis: Long barbels.

Catfish Association Great Britain: Volume 1. 1983, 138p.
Reis, Roberto E. 1996. Dianema Cope 1872. Version 29 April 1996. The Tree of Life Web Project.

Photo Credits

First image: © Allan James @

Second image: © Mark Duffill