Zawadzki's Corydoras

Geographical Origin and Habitat: This freshwater armored catfish is native to South America, recently described from the Rio Madeira basin (specifically within the Rio Aripuanã drainage) in the state of Mato Grosso, Brazil. It inhabits clear to slightly amber forest streams (igarapés) characterized by slow-to-moderate current, sandy riverbeds, and abundant leaf litter, submerged branches, and shoreline root systems.

Taxonomy and Morphology: Belongs to the Callichthyidae family, Corydoradinae subfamily, and Corydoras genus. Scientifically described in 2016. It is distinguished as a long-snouted Corydoras species. Adults reach a maximum standard length of approximately 5.0 cm. It features a robust body protected by dual rows of overlapping bony plates (scutes) and sensitive barbels around its mouth.

Social Behavior: A peaceful and highly gregarious schooling fish that must be housed in groups of at least 6 individuals of its own species. It spends its time almost exclusively on the bottom, sifting through the sandy substrate with its barbels to locate micro-fauna. It exhibits active foraging behavior during both day and night.

Coloration and Sexual Dimorphism: Body coloration features a light greyish to silver-beige base, covered with fine dark spots and flecks across the head and flanks, which sometimes form irregular patterns. Fins are translucent with faint dotted markings. Sexual dimorphism is apparent in mature specimens: females are noticeably larger, rounder, and wider than males.

Aquarium Setup: Requires an aquarium of at least 80 liters (approx. 20 gallons) to accommodate a small school. The most critical setup requirement is a substrate of fine, smooth sand (avoid sharp gravel) to prevent damage and infection to their delicate barbels. Decorate with driftwood, leaf litter, and live plants to provide sheltered, shaded resting areas.

Diet and Feeding: An omnivorous bottom feeder. In captivity, it should not be expected to live on tank scraps alone. Provide a dedicated diet of high-quality sinking catfish pellets or tablets, supplemented regularly with small live or frozen foods such as bloodworms, tubifex, brine shrimp, and daphnia to maintain optimal health.

Water Quality: Prefers clean, well-oxygenated water with efficient filtration that does not create strong surface turbulence. Maintain water temperature between 22 and 26°C, pH between 6.5 and 7.5, and soft to moderate hardness. Regular partial water changes (15-20% weekly) are essential to prevent organic waste from building up on the sand.

Compatibility and Cohabitation: An ideal resident for peaceful community tanks. It coexists peacefully with small tetras, rasboras, pencilfish, hatchetfish, and other peaceful community species. Do not house with large, aggressive cichlids, predatory fish, or boisterous bottom dwellers that might compete aggressively for territory and food.

Aquarium Breeding: Breeding follows typical Corydoras patterns. Spawning is triggered by substantial water changes using water that is slightly cooler (simulating the onset of the rainy season) and feeding high-protein live foods. They deposit adhesive eggs on plants or glass. Parents do not care for the eggs and must be removed to prevent predation.

Risks and Diseases: The primary risk is barbel erosion and subsequent secondary bacterial infections caused by coarse, sharp substrate or high organic buildup in the sand. They are sensitive to high nitrate levels and copper-based medications or salt, which should be used with extreme caution if treatment is necessary.