Three-stripe Corydoras Breeding Guide

How to breed three-stripe corydoras (Corydoras trilineatus): sexing, a cool-water-change trigger, the T-position spawn, and fry care.

Overview

The three-stripe corydoras (Corydoras trilineatus), often sold as the false julii cory, is a small South American catfish reaching about 4-6 cm. Like other Corydoras it is an egg-layer that spawns in the T-position; it is a little more demanding to breed than the very hardiest species.

Sexing

Females are noticeably rounder and broader-bodied than males, especially when full of eggs, and are often slightly larger. Males stay slimmer.

Conditioning

Condition the group on a varied diet of live, frozen and dried foods. A ratio of about two males per female is recommended for reliable fertilisation.

Breeding Setup

Use a tank of around 18 x 12 x 12 inches with a bare base, sand or fine gravel, and gentle sponge or box filtration to protect fry. Soft, slightly acidic water suits the species, with temperature around 24 C (about 75 F) and pH near 6.5; peat filtration or RO water is beneficial.

Spawning Behavior & Trigger

When the females are visibly full of eggs, perform a large 50-70% water change with cooler water and increase oxygenation and flow, repeating daily until the fish spawn. A receptive female lets the male caress her with his barbels before the pair take up the T-position, in which the male grasps the female's barbels. She then deposits a single egg (occasionally up to four) at a time on the glass.

Egg & Fry Care

Eggs hatch in about 3-5 days. Once the yolk sacs are absorbed the fry accept microworm and brine shrimp nauplii. The fry seem less prone to disease when kept over a thin layer of sand, and clean water with regular changes supports their growth.

Common Challenges

As with other Corydoras, eggs are vulnerable to fungus and to being eaten by adults, so separating eggs or adults is usual. Stable, soft water and a reliable cool-change routine are the main keys to triggering a spawn.