Breeding Corydoras gladysae

Breeding guide for Corydoras gladysae, a cool-water high-altitude Argentinian cory: a T-position egg-depositor essentially absent from the hobby.

Overview

Corydoras gladysae Calvino & Alonso, 2010 is a small cory endemic to the Rio Calchaqui watershed in Salta province, northwestern Argentina, reaching roughly 30-37.5 mm standard length (Seriously Fish). Its habitat is cool, hard and salt-rich water; Seriously Fish records a temperature of 8-16 C, pH 7.5-8.5 and hardness of 179-357 ppm. The species is essentially absent from the aquarium hobby, and no dedicated reproduction details are documented for it, so the standard Corydoras pattern is the only available reference.

Sexing

In Corydoras generally, mature females grow larger and become noticeably rounder and broader-bodied than males, particularly when in spawning condition; this is the most reliable visual cue for this species in the absence of species-specific data.

Conditioning

Given the high-altitude, snow-melt origin of its native river, this is a cool-water species rather than a tropical one. Condition adults on varied live and frozen foods while maintaining the cooler, harder water its habitat indicates.

Spawning Behavior & Trigger

Corydoras are characteristically induced to spawn with a large, cooler water change that mimics seasonal rain. The pair then adopt the classic 'T' position in which the female collects sperm from the male before depositing eggs, cupped in her pelvic fins, onto a firm surface.

Egg & Fry Care

As an egg-depositor the species attaches eggs to plants, rock or glass and provides no parental care. Eggs may be left in place or transferred for rearing, and hatched fry are raised on fine powdered foods followed by microworm and Artemia nauplii, as for other corys.

Common Challenges

The dominant challenge is the cool, hard, alkaline water this species requires, which differs markedly from typical tropical Corydoras set-ups; combined with its near-total absence from the trade, obtaining and conditioning stock is difficult.