Olive Corydoras CW019

CW019 is an undescribed olive-toned Gastrodermus with a subdued greenish-brown to beige body and darker mottling or broken lateral marks. Because it remains a trade-code form, identification should be based on reliable CW019 provenance rather than colour alone.

Identify this profile by the combination of an olive to bronze body with subdued darker markings and an elegant streamlined profile. Older sources commonly list this fish as Corydoras sp. CW019; the current profile follows the accepted or revised placement Gastrodermus sp. CW019. The code CW019 should remain attached to the name until the population is formally described and unambiguously assigned. 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.

Reliable external sex differences have not been well documented for this form. Mature females are likely to become broader through the abdomen than males, as in related Corydoradinae, but juveniles and unconditioned adults should not be sexed by colour alone.

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 to moderately hard, slightly acidic to neutral water is suitable. Provide good oxygenation and keep ammonia and nitrite at zero.

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.