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his is one of my favourite Corydoras species. It is of course very small, but has a very pretty colour pattern, in that well looked after specimens will have black chevron markings running from the caudal peduncle to the mid-dorsal area. There can also be a golden lateral line running through the body and a black blotch to the dorsal, the underside is white.

Gastrodermus pauciradiatus

It is still known in the scientific community as Aspidoras pauciradiatus but it is certainly a Corydoras and when it is reclassified it will be placed in Lineage 5 the "Elegans group". A revision could involve the resurrection of the genus name Gastrodermus (Cope, 1878) with the designated type species of C. elegans. C. pauciradiatus has 6 soft rays in the dorsal while the rest of the genus has 7, (pauciradiatus means, few fin rays).

In earlier aquatic literature this species was erroneously captioned as Hoplisoma cochui a small species very similar to Hoplisoma habrosus from Brazil. As mentioned, specimens in good condition, especially females, will have black markings that will stand out and usually sends a signal to the aquarist that they are happy in their surroundings.

The above (very bad!) photo shows the one youngster from my January 2001 spawning. You can just see the fantastic black colouration in the caudal fin and also in the dorsal. My breeding experience of this species you can read about further down in the reproduction table.

Remarks: Corydoras pauciradiatus when reclassified will be placed in Lineage 5 the "Elegans group". A revision could involve the resurrection of the genus name Gastrodermus (Cope, 1878) with the designated type species of C. elegans. As of the latest update Corydoras pauciradiatus has now been placed in Lineage 5 and has the new genus name of Gastrodermus (2024).

False Corydoras

Aspidoras pauciradiatus, Corydoras pauciradiatus

Corydoradinae

South America: Brazil : Upper Araguaia River basin. Type locality: Brazil, Rio Araguaia, near Aruanã, Est. Goiás (14º58'S, 51º04'W).

Male: 2.5cm (1ins) Female: 3.0cm (1¼ins)

22-25°C (71-77°F)

6.0-7.0.

Dorsal 1/6; Anal i,6; Pectorals; 1/7; Ventrals 1/5. 23 Dorsolateral body scutes. 20 Ventrolateral body scutes. 2 pre-adipose scutes.

Ground colour of head and body pale tan. No mask present but melanophores dense between eyes and on top of head producing a dark brown colour. Top of snout pale brown with 7-8 moderate sized black spots in a triangular pattern with one end of triangle at tip of snout. Small black spots on head and body, the spots on the body tend to be in rows which converge into the scute junctions. (The effect vaguely resembles a series of posteriorly pointing chevrons). Belly region pale tan, without dark pigment. Dorsal fin with a large black blotch at the base, with one or two narrow horizontal bands above. Pigment of these bands confined to the fin rays. Pectoral and ventral fins clear. Anal fin with one or two rows of pigment, confined to the fin rays and formimg a band. Adipose fin with some on the spine. Caudal fin with about five rows of narrow black bars, third from anterior band being the darkest, this pigment confined to the fin rays.

Gastrodermus pauciradiatus does not do well in a mixed community tank with larger tankmates due to its size and retiring nature. A better idea is a smaller tank with small characins/tetras or even a tank on their own. Buy at least 6 or more as they do better in their own company and when settled will come to the front of the tank at feeding time. I find that Java Moss and Java Fern plants with a sand substrate and a box or sponge filter in a 18" x 12" x 12" tank will keep them happy, with weekly water changes of 30 to 50% adequate.

Very difficult to breed but has been done on a few ocassions. They do tend to eat their eggs, so removing parents or eggs after spawning is a good idea. They lay their eggs in Java moss or on the aquarium glass and you can raise the young as per the Corydoras/Gastrodermus genus. Update: I did manage to spawn this species after many years of frustration (Jan.2001). Tank parameters were: 18" x 10" x 10" with loads of Java Moss and a sand substrate. I added an internal pump to the sponge filter which already resided in the tank to really make the water move around the tank. I carried out a 75% cool water change and they laid 40 eggs on the outside of the internal power filter. I then removed the very small eggs to a small rearing tank. The temperature was 77f, p.H 6 and GH 1. I only managed to raise one fry as the rest of the eggs fungused, but now that they have spawned once the chances are greatly enhanced for a second spawning.

Prefers small live food such as newly hatched brine shrimp but will also take small frozen foods and good quality crushed flake food, plus tablet food.

Gastrodermus: The lining membrane of the alimentary tract of an invertebrate, used especially when the germ-layer origin is obscure.
pauciradiatus: With few (fin) rays (6 rays in dorsal.)

Alexandrou, Markos & Taylor, Martin. (2011). Evolution, ecology and taxonomy of the Corydoradinae revisited.
Angelica C Dias, Luiz F C Tencatt, Fabio F Roxo, Gabriel de Souza da Costa Silva, Sérgio A Santos, Marcelo R Britto, Martin I Taylor, Claudio Oliveira, Phylogenomic analyses in the complex Neotropical subfamily Corydoradinae (Siluriformes: Callichthyidae) with a new classification based on morphological and molecular data, Zoological Journal of the Linnean Society, 2024;, zlae053.
Ferraris, C.J. Jr., 2007. Checklist of catfishes, recent and fossil (Osteichthyes: Siluriformes), and catalogue of siluriform primary types. Zootaxa 1418:1-628.
Ian A. M. Fuller & Hans-Georg Evers (2011). Identifying Corydoradinae Catfish Supplement 1. Ian Fuller Enterprises.

Photo Credits

Top:       © Ingo Seidel @
Bottom:   © Allan James @