Corydoras CW-049

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The Corydoras CW-049, also sold as Black Diamond, is an ornamental corydoras identified by the CW-049 code. This form is sought after for its dark coloration and peaceful schooling behavior. Native to the Rio Negro in Brazil, it is associated with soft, acidic, tannin-stained water typical of flooded forest habitats. Because this fish is wild-collected, acclimation deserves particular attention. With a rarity level of 2, the Black Diamond is relatively uncommon and will appeal especially to aquarists who appreciate locality-associated corydoras.

General description

Corydoras CW-049 is a small corydoras belonging to the Callichthyidae family. The CW-049 code refers to an aquarium and trade form rather than a binomial species name. Its main appeal lies in its dark coloration, stocky body and schooling habits. Like other corydoras, it spends most of its time near the bottom, using its barbels to explore the substrate and locate food. It should be kept in a group of at least six fish, preferably more, to encourage natural behavior. Usually shy when newly introduced, it becomes more active once settled. A mature, well-oxygenated aquarium with a fine sand substrate is especially suitable.

Geographical origin and biotope

The geographical reference associated with CW-049 is the Rio Negro in Brazil, a major tributary of the Amazon. Its natural environment includes quiet or moderately flowing areas, flooded margins and sections shaded by forest. The water is generally soft, acidic and rich in tannins released by leaves, branches and decomposing organic matter. In the aquarium, gentle but effective filtration, subdued lighting and driftwood help recreate this atmosphere. Aquarium-safe leaf litter can provide shelter and release humic compounds. Water quality remains the priority: stable, clean and well-oxygenated water is more important than an exact biotope replica.

Precise locality and local name

The most commonly used trade name for this form is Black Diamond. The CW-049 code distinguishes it in the trade from other undescribed corydoras or fish offered under collection numbers. The reference to the Rio Negro places its origin in the Brazilian Amazon basin, but a more precise collection locality is not used here. Among aquarists, Corydoras CW-049 therefore remains the most practical designation, while Black Diamond mainly describes its appearance. Since this is a wild fish, it is best to retain the provenance information supplied with the shipment and avoid mixing different localities under the same trade name.

Appearance and physical characteristics

Black Diamond has a short, sturdy body, a subterminal mouth surrounded by barbels and a triangular dorsal fin. Its most distinctive feature is a black to charcoal-gray coloration, sometimes enhanced by metallic tones depending on lighting, mood and acclimation. As in other corydoras, the lateral bony plates provide natural protection, while the fin spines can catch in a fish net. The eyes are proportionate to the body and the fins are generally translucent to dark. Adult size is around 5 cm, excluding fin filaments. A pale substrate, driftwood and moderate lighting can enhance its visual contrast.

General diet

Corydoras CW-049 is an omnivorous bottom feeder that searches for small organisms, organic debris and microscopic prey in the substrate. In the aquarium, its diet should combine quality sinking wafers, foods designed for bottom fish and regular offerings of frozen foods such as bloodworms or brine shrimp. Food should reach the bottom quickly so the corydoras can feed without excessive competition. Evening feeding can work well because activity often increases as the lights dim. Do not rely on leftovers from other fish. Variety, a clean substrate and reasonable portions support good condition without unnecessarily polluting the water.

Essential data

• River of origin: Rio Negro
• Local name used: Black Diamond
• Origin of the scientific name: CW-049 is a collection and trade code for a corydoras not described under a binomial name
• Common/vernacular names: Black Diamond, Corydoras CW-049
• Family: Callichthyidae
• Subfamily: Corydoradinae
• Name pronunciation: kor-ee-DORE-us see double-you zero four nine
• Maximum adult size: about 5 cm
• Water temperature and pH: 24 to 28 °C; pH 5.5 to 7.0
• Watercourse appearance and surrounding vegetation: dark tannin-stained water, shaded margins, roots, leaf litter and flooded-forest vegetation
• Typical tankmates: Corydoras agassizi, Hemigrammus rhodostomus
• Temperament and behavior: peaceful, social, bottom-oriented and often more active in subdued light
• Bottom structure and flow: fine sand, leaves and roots; low to moderate flow
• Wild-collected species: yes; gradual acclimation is recommended
• Rarity: level 2 out of 3, relatively uncommon

In your aquarium

To successfully keep Corydoras CW-049, focus on a mature aquarium, stable water and a properly sized group. Fine sand protects its barbels, while driftwood, leaf litter and shaded areas help reduce stress. Because this shipment is wild-collected, slow acclimation, close observation and a varied diet are especially important. Avoid aggressive tankmates, sharp substrates and waste buildup on the bottom. Regular water changes, good oxygenation and moderate flow will help keep this corydoras healthy.