Gladys's Cory

Geographic Origin and Biotope: Argentine species, endemic to the Salta province (Calchaquí River basin). Frequents high altitudes and clear, cool Andean waters, flowing over bottoms of sand mixed with round rocks, in highly oxygenated zones.

Taxonomy and Morphology: Small-sized Corydoras, hardly exceeds 4 cm (1.6 inches). Very rounded snout and particularly stocky and tall body. Discovered recently (2010), belongs to the "southern" tribe of the genus, adapted to colder waters compared to tropical species.

Social Behavior: Calm but tenacious worker. Tends to stay compacted in a school out of biological necessity: if isolated, it falls into rapid depression or lethargy. Group dynamics involve synchronous dashes and choral resting periods under plants.

Coloration and Sexual Dimorphism: Brown or grayish-brown coloration on a pale background, arranged in large irregular spots or reticulations. True defined dark bands are missing. Mature females have an obvious "barrel" shape, surpassing the males in size.

Aquarium Setup: Being from high altitude, the tank must have strong water current (simulating Andean streams) and oxygenation at maximum levels. Sandy bottom, smooth stones, and moderate vegetation. Does not necessarily require a dark blackwater environment.

Diet and Feeding: Bottom micropredator. Given the very small size of the mouth, it requires very fine baits: microgranules for corydoras and daily introductions of baby brine shrimp, microworms, and tiny frozen bloodworms.

Water Quality: Tolerates cold very well. Must not exceed 25-26°C (77-79°F) for long to avoid collapsing. The optimum is 20-23°C (68-73°F). Requires clear waters, low or medium hardness (GH 2-12), and pH 6.0-7.4. Intolerant to the accumulation of polluting sludge (NH3/NO2/NO3).

Compatibility and Tankmates: Excellent for temperate (unheated) aquariums with suitable companions: Gymnocorymbus ternetzi, Aphyocharax, or small Argentine Loricariids. Proves to be a sacrificial victim if inserted with large cichlids that would dominate the limited bottom resources.

Aquarium Reproduction: Stimulated by simulating cold mountain rains through copious water changes. Couples lay small quantities of highly adhesive eggs among rocks and mosses. High predation rate by the rearing colony itself.

Risks and Diseases: High temperatures induce chronic hypoxia leading to lethal attacks by Columnaris. Housing on rough, unpolished substrates inevitably flakes the epidermis of the barbels making feeding impossible.