Blacktop Corydoras

Geographic Origin and Biotope: Amazon River basin (Ecuador and northern Peru). Prefers small tributaries, oxbow lakes and shady forest rivers with a bottom of sand or soft clay, covered by leaf litter.

Taxonomy and Morphology: Black-Top Corydoras (Corydoras acutus). A "long-snouted" corydoras, specialized for sinking its head deeply into the soft substrate in search of prey. The mouth is equipped with sensitive barbels.

Social Behavior: Exquisitely peaceful and highly gregarious. Essential to keep them in schools of no less than 6 specimens, otherwise they will suffer lethal stress, chronic shyness and food refusal. Spends the day rummaging the bottom.

Coloration and Sexual Dimorphism: Presents a silvery/gray body heavily dotted and spotted with black. The distinctive feature is the black spot (black-top) on the upper dorsal fin and the elongated snout. Females are visibly wider and taller than males.

Aquarium Setup: Tank of minimum 80 cm (32 inches). THE BOTTOM MUST BE FINE SAND. Any angular gravel or sharp quartz will irreparably wear away the delicate barbels, causing lethal fungal infections. Wood and dry leaves complete the layout.

Diet and Feeding: Bottom micro-predator. Requires sinking protein-rich pellets and a constant supply of frozen food (bloodworms, brine shrimp, tubifex). Avoid feeding them only with the "scraps" of surface fish.

Water Quality: Loves very well oxygenated waters (essential for corydoras) and moderate temperatures (24°C / 75°F ideal). Nitrates strictly below 20 ppm; they are bottom fish and are immediately affected by the accumulation of pollutants on the ground.

Compatibility and Tankmates: Absolute pacifists. Perfect companions for Discus, Angelfish, small and large Characins (Tetras) and dwarf Cichlids (e.g. Apistogramma, although during spawning the latter will brutally chase them away).

Aquarium Reproduction: Long-snouted Corydoras are harder to breed than short-snouted ones. Requires sudden stimulation: a massive change of very cold water (monsoon simulation) prompts the female to glue the eggs on the glass in strong current.

Risks and Diseases: Lethal bacterial infections to the barbels caused by poor bottom hygiene (anaerobic bacteria). They emit toxins if threatened or transported in bags with little water.