Northern Cory

Geographic Origin and Biotope: Endemic to the northern Orinoco River basin, between Venezuela and Colombia (hence "septentrionalis" = northern). Inhabits quiet river oxbows, residual pools, and slow, shaded streams with sandy or muddy bottoms.

Taxonomy and Morphology: Northern Corydoras (Corydoras septentrionalis). Belongs to the long-snouted Corydoras group. Features an elongated and pointed cranial profile which it uses to probe deeply into the substrate in search of hidden prey.

Social Behavior: Highly gregarious. Despite being slightly larger than other Corys, it is extremely peaceful. The group (minimum 6-8 specimens) constantly explores the bottom in a loose formation, always maintaining visual contact.

Coloration and Sexual Dimorphism: Light base livery covered by a dense network of dark spots and very fine wavy lines extending over the snout and body. Barred caudal fin. Adult females are plumper, with a visibly swollen abdomen.

Aquarium Setup: Very fine sand is an essential requirement, even more so than for short-snouted Corydoras, since this species literally buries its entire snout in the substrate to feed. Add roots to create hiding places.

Diet and Feeding: Benthic omnivore. The shape of its snout makes it an excellent extractor of hidden bloodworms and tubifex. Accepts quality pellets for bottom fish, but has a higher protein requirement derived from live/frozen prey.

Water Quality: Adapts well to both weakly acidic and neutral waters (pH 6.0-7.5), but is uncompromising on bottom hygiene. Accumulation of detritus and nitrates causes bacterial infections to the long sensory barbels.

Compatibility and Tankmates: Ideal companion for Orinoco biotopes. Perfect with Tetras (e.g. Cardinals, Hemigrammus), Hatchetfish on the surface, and quiet Loricariids. Avoid large or medium Cichlids (e.g. Geophagus) that compete for the bottom.

Aquarium Reproduction: Achieved with drastic cold water changes that simulate the onset of the wet season. The female lays very large, adhesive eggs on the leaves of strong plants or on the glass, in areas with strong current.

Risks and Diseases: Vulnerable to barbel wear caused by sharp gravel bottoms. Copper compounds and anti-snail medications can quickly prove lethal given their scale-less anatomy.