Nijssen’s Corydoras

A small, delicate Gastrodermus with a pale body, dark lateral markings and a distinct dark patch near the tail base. Pattern can appear as a broken stripe or scattered blotches, and its streamlined build is lighter than that of common corys.

Identify this profile by the combination of a small elegant form with a dark lateral stripe and noticeable differences in adult male and female pattern. Older sources commonly list this fish as Corydoras nijsseni; the current profile follows the accepted or revised placement Gastrodermus nijsseni. Colour alone can be unreliable in stressed, juvenile, or poorly conditioned fish, so body shape, snout length, fin pattern, and provenance should also be checked.

Females are usually broader and fuller through the abdomen, while males remain slimmer. Colour and pattern overlap strongly between the sexes, so body shape in mature fish is the safer guide.

Keep a sizeable group in a mature aquarium with fine sand, gentle open swimming room above the bottom, plants or wood for cover and consistently clean, oxygen-rich water. These fish may spend more time away from the substrate than many corys, so avoid crowding the lower and middle levels.

A peaceful, coordinated shoaling fish that often uses the lower and middle water as well as the substrate. A small group can appear nervous or inactive, while a larger group shows more natural hovering, darting and foraging behaviour.

Keep at least 8 of the same species or coded population, with 10 or more preferred where space permits. A mixed collection of single corys does not fully replace a proper same-species group.

It is not territorial. Males may briefly chase one another or follow females during courtship, but sustained aggression is unusual when the group has adequate floor space.

Works best with small, peaceful midwater fish and other gentle bottom species. Avoid aggressive or highly competitive tank mates, and do not assume dwarf shrimp young will be safe from opportunistic feeding.

Soft, mildly acidic water best reflects the natural habitat and usually gives the most reliable breeding results. Stable clean water is more important than forcing an exact pH.

Use small sinking or slow-falling foods, including quality micro-pellets, wafers and varied frozen or live invertebrate foods. Feed across more than one area because these fish may take food in the lower water as well as from the substrate.

Feed after faster surface and midwater fish have taken their share, and confirm that every individual reaches food. Use small portions once or twice daily, remove persistent leftovers, and vary prepared and frozen or live foods.

Detailed aquarium breeding records are limited. It is expected to use the usual Corydoradinae T-position and attach adhesive eggs to firm surfaces, but triggers, egg output and fry requirements should not be presented as reliably established for this species.