Little corydoras (Corydoras nanus) care guide

Group
Freshwater fish
Other names
Nanus cory, Little cory, Gastrodermus nanus, Corydoras nain
Family
Callichthyidae (armoured catfishes)
Origin
Suriname and French Guiana in north-eastern South America: the Maroni (Marowijne) basin, including the Gran Rio, and the Iracoubo river basin.
Water
freshwater
Maximum size
5 cm
Temperature
22–26°C
pH
6–8
Hardness
3–18 dGH (estimated)
Minimum tank
54 litres
Care level
intermediate
Temperament
peaceful

Care

A slim, active cory from the Guianas. Keep it in a group of at least six of the same species; in a bigger group it is bolder and you will see much more natural behaviour. A tank with a base of about 60 × 30 cm (around 54 litres) suits a group – this is our estimate, as PlanetCatfish gives no tank size. Use soft sand or smooth, rounded gravel, never sharp-edged gravel, so the barbels are not damaged. PlanetCatfish recommends shade from overhanging rockwork, arching bogwood and tall or floating plants, with open sand in front for feeding. PlanetCatfish gives a temperature of 22–26 °C. Neither it nor FishBase gives firm pH or hardness figures; clean, soft to moderately hard water near neutral is the usual cory approach. Keep the water clean with regular partial changes and a tidy substrate, and take care with salt and medications, which corys tolerate poorly. Females are noticeably larger and fuller-bodied when seen from above; males develop more pointed fins as they mature. Like other corys it has twin rows of armour plates along the flanks and gulps air at the surface now and then, which is normal. PlanetCatfish now lists it as Gastrodermus nanus, following the 2024 split of Corydoras; it is still sold as "Corydoras nanus". PlanetCatfish describes true C. nanus as rare in the hobby, and similar small striped corys are sometimes sold under the name, so buy from a seller who can confirm the origin. The French name "Corydoras nain" simply means "dwarf cory". Sources: PlanetCatfish (planetcatfish.com/common/species.php?speciesid=621). Checked October 2026.

Diet

An omnivorous bottom forager. Feed good sinking foods such as small tablets, granules and pellets every day, and add live or frozen foods such as bloodworm, Daphnia and small worms several times a week. Make sure food reaches the bottom rather than relying on leftovers.

Breeding

PlanetCatfish has no breeding reports for this species. A general cory approach – conditioning a group with more males than females on plenty of live and frozen food, then a large, slightly cooler water change – is the usual way to try.

Compatibility and tank mates

A peaceful community fish. Keep it with small, gentle tankmates such as tetras, pencilfish, rasboras and dwarf cichlids, and avoid anything large enough to see it as food or boisterous enough to take all the food on the bottom.

Last updated 5 October 2026. Community-edited care guide on Aquatic-Auctions.

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