Corydoras schwartzi Breeding Guide

Breeding Schwartz's Cory (Corydoras schwartzi): sexing, conditioning, soft-water cooler-change trigger, T-position spawning and raising fry.

Overview

Corydoras schwartzi, Schwartz's Cory, is endemic to the Rio Purus drainage in Brazil and grows to about 7 cm. It is an egg-depositing catfish that spawns in the genus's typical T-position. The species is often misidentified in the trade, so confirm identity before pairing.

Sexing

Seriously Fish reports that females are noticeably rounder and broader-bodied than males, especially when full of eggs, and are often slightly larger.

Conditioning

Condition the group on a varied diet of live, frozen and dried foods. Seriously Fish recommends a 2:1 male-to-female ratio.

Breeding Setup

Seriously Fish suggests a tank around 18 by 12 by 12 inches with a bare bottom, sand or fine gravel, sponge or box filtration and Java moss clumps. Target around 24 degrees C (75 F) and pH 6.5; peat filtering and RO water are recommended. Maintenance parameters are 22-24 degrees C, pH 6.0-7.5 and hardness 1-15 dH.

Spawning Behavior & Trigger

Trigger spawning with large 50-70% water changes using cooler water, increasing oxygenation and flow, repeated daily until the fish spawn. In the T-position the male grasps the female's barbels between his pectoral fin and body and releases sperm; the female deposits a single egg (although up to four may be released) into her pelvic-fin basket and attaches it to a surface.

Egg & Fry Care

Seriously Fish gives a hatch time of 3-5 days. Once the fry have absorbed their yolk sacs they accept microworm and brine shrimp nauplii, and do better over a thin sand layer than on a bare bottom.

Common Challenges

Frequent trade misidentification means tank groups may mix similar species; verify identity to avoid hybrids. Fungused eggs and poor water quality are the usual causes of losses, so keep eggs and fry in clean, well-oxygenated water.