Corydoras agassizii Breeding Guide

How to breed Agassiz's Corydoras (Corydoras agassizii): sexing, conditioning, the cooler-water spawning trigger, T-position pairing and fry care, based on the documented genus pattern.

Overview

Corydoras agassizii is an armoured catfish of the family Callichthyidae reaching about 60-70 mm standard length. Its type locality is the Amazon River near Tabatinga, at the Brazil-Peru-Colombia tripoint, and it ranges at least as far as Iquitos in Loreto, Peru (Seriously Fish). It is a peaceful, social egg-depositor best kept in groups. First-hand spawning accounts specific to this species are limited, so the steps below follow the established Corydoras genus pattern; treat species-level figures as approximate.

Sexing

Females grow larger and, when sexually mature, are noticeably rounder and broader-bodied than males, particularly when gravid (Seriously Fish). Viewing fish from above makes the fuller female outline easiest to identify.

Conditioning

Feed a varied diet of sinking dried foods plus small live and frozen items to bring females into condition. The species is a foraging bottom-dweller and should be offered food that reaches the substrate rather than being left to scavenge leftovers. Maintaining the group in at least four to six individuals encourages natural social behaviour and improves spawning readiness (Seriously Fish).

Breeding Setup

Use a dedicated tank with fine sand or a bare base, sponge filtration and fine-leaved plants or spawning mops. Soft sand is preferable because the species feeds by sifting the bottom and is vulnerable to barbel damage on sharp gravel. Keep the water within the species' tolerated range of pH 6.0-8.0 and roughly 22-27 degrees C (Seriously Fish), favouring the softer, slightly acidic end for conditioning.

Spawning Behavior & Trigger

Spawning across the genus is triggered by a large (50-70%) cooler water change with raised oxygenation and flow, repeated daily; this mimics the influx of cooler, oxygen-rich rainy-season water. In the T-position the male clasps the female's barbels while she cups eggs in a pelvic-fin basket and gathers milt, then deposits the adhesive eggs on glass, leaves or a mop. The female makes repeated passes, depositing small batches over the course of a spawning session. Exact egg counts for C. agassizii are not recorded in the consulted sources.

Egg & Fry Care

Because adults predate eggs, remove either the parents or the eggs after spawning. Genus eggs generally hatch in about 3-5 days; once the yolk sac is absorbed the fry take microworm and newly hatched brine shrimp. Stable, clean water and a thin sand layer support early growth, and frequent small water changes help maintain quality without shocking the fry.

Common Challenges

Key challenges include conditioning females fully, delivering a consistent cooler-water trigger, and preventing egg predation. Egg fungus on infertile eggs and water-quality lapses during the fry stage are the commonest causes of loss.