Corydoras griseus HOLLY, 1940

SynonymsTop ↑

Corydoras griseus deweyeri Meinken, 1957

Etymology

Corydoras: from the Ancient Greek κόρυς (korus), meaning ‘helmet’, and δορά (dora), meaning ‘skin, hide of an animal’, in allusion to the rows of bony plates on the flanks of genus members.

griseus: from the Latin griseus, meaning ‘grey’, presumably in allusion to this species’ somewhat uniform greyish colour pattern.

Classification

Order: Siluriformes Family: Callichthyidae

Distribution

Native to Guyana, where it may be restricted to the Potaro River, a major tributary within the Essequibo watershed.

It was described from aquarium specimens which were said to have been collected in ‘very small water courses of the Amazon’, but the type locality was corrected to ‘Guyana-Essequibo, Potaro River, Kuribong trail’ by Nijssen and Isbrücker (1980).

Maximum Standard Length

40 – 50 mm.

Aquarium SizeTop ↑

Minimum base dimensi0ns of 90 ∗ 30 cm are recommended.

Maintenance

Ideally use a substrate of fine sand, although rounded gravel is an acceptable alternative provided that it is kept scrupulously clean.

Other décor is largely down to personal choice, but some cover should be provided to give the fish security.

Water Conditions

Temperature: 20 – 26 °C

pH: 6.0 – 7.5

Hardness: 36 – 215 ppm

Diet

Corydoras spp. are foraging omnivores, and most will accept most sinking dried foods as well as small live and frozen varieties such as chironomid larvae (bloodworm), Tubifex, etc.

Feeding a varied diet will ensure the fish are in optimum condition.

Under no circumstances should they be expected to survive on ‘left-overs’ from other inhabitants of the aquarium or relied on to ‘clean’ the aquarium.

Behaviour and CompatibilityTop ↑

Peaceful and gregarious. Should be maintained in a  group of at least 4-6 individuals.

Sexual Dimorphism

Females tend to grow larger, and sexually mature individuals are noticeably broader and deeper-bodied than males.

Reproduction

Can be bred in a similar fashion to many other Corydoras species.

Use a ratio of two or more males per female if possible, and when the females are visibly full of eggs perform a large (50-70%) water change with cooler water, and increase oxygenation and flow in the tank. Repeat this daily until the fish spawn.

Eggs may be deposited on the aquarium glass, among fine-leaved vegetation or within sunken spawning mops, with the latter particularly recommended since they facilitate easy removal of eggs.

Once spawning is complete either adults or eggs should be removed; the latter can usually be rolled gently up the glass with a finger. The new container should contain the same water as the spawning tank and be similarly well-oxygenated.

Most breeders add a few drops of methylene blue, or an alder cone or two at this point in order to prevent the eggs developing fungus.

Incubation is normally 3-4 days and once the fry have fully-absorbed their yolk sacs they are able to accept small live foods such as microworm, Artemia nauplii, etc.

They are not the easiest to raise, requiring excellent water quality, but seem less susceptible to ailments when maintained over a thin layer of sand rather than in a bare arrangement.

NotesTop ↑

Two similar-looking fishes have been collected in Rondônia state, northwestern Brazil, and assigned the ‘C’ numbers C040 and C073, respectively, while C134 from Amapá state is also comparable.

The genus Corydoras is included in the family Callichthyidae, of which members are often referred to collectively as ‘armoured’ or ‘mailed’ catfishes group due to the presence of bony plates in place of scales on the body.

Their taxonomy can be confusing, and numerous undescribed species are also thought to exist. Fish of unconfirmed identification entering the aquarium hobby are therefore typically assigned a ‘C’ or ‘CW’ number for purposes of reference and organisation.

They are facultative air breathers and possess a modified, highly vascularised intestine which has evolved to facilitate uptake of atmospheric oxygen and aid survival in oxygen-deprived environments. In the aquarium you’ll occasionally see them rising to the surface to take in gulps of air.

The stiffened pectoral-fin spines are capable of piercing human skin and a ‘sting’ can be very painful indeed, so care should be exercised when handling them.

It is thought that secretions from the axillary glands at the base of each spine may even be mildly toxic or venomous.

References

1. Holly, M., 1940 - Anzeiger der Akademie der Wissenschaften in Wien v. 77: 107-112
   Vier noch nicht beschriebene Corydoras Arten.
2. Reis, R. E., S. O. Kullander and C. J. Ferraris, Jr. (eds), 2003 - EDIPUCRS, Porto Alegre: i-xi + 1-729
   Check list of the freshwater fishes of South and Central America. CLOFFSCA.
3. Ferraris, C. J., Jr., 2007 - Zootaxa 1418: 1-628
   Checklist of catfishes, recent and fossil (Osteichthyes: Siluriformes), and catalogue of siluriform primary types.
4. Fuller, I. A. M., and H-G. Evers, 2005 - Verlag A. C. S. GmbH: 1-384
   Identifying Corydoradinae Catfish.
5. Nijssen, H. and I. J. H. Isbrücker, 1980 - Bijdragen tot de Dierkunde 50(1): 190-220
   A review of the genus Corydoras Lacépède, 1803 (Pisces, Siluriformes, Callichthyidae).