Corydoras sychri Breeding Guide

How to breed Sychr's Corydoras (Corydoras sychri): documented spawning, the female's 2-4 egg pelvic basket, ~100 eggs total, hatch in 4-6 days and fry care.

Overview

Corydoras sychri, Sychr's catfish, is a small armoured catfish reaching a maximum length of about 1.7 inches (4.3 cm). It occurs in the Nanay River basin in Loreto, Peru (Wikipedia). It is a peaceful egg-depositor and, unlike many congeners, has documented spawning behaviour recorded for the species.

Sexing

As in the genus, mature females are the broader, fuller-bodied sex, most evident when they are carrying eggs and viewed from above. Detailed species-specific sexing notes are limited in the consulted sources, but the rounder, egg-filled female body is the practical guide.

Conditioning

In the wild the species feeds on worms, benthic crustaceans, insects and plant matter (Wikipedia). Conditioning on a varied diet of similar live, frozen and dried foods brings females into spawning condition, and keeping the fish in a group encourages the social behaviour that precedes spawning.

Breeding Setup

Provide soft, slightly acidic water and dense vegetation for egg attachment, along with a fine sand base that suits this bottom-dwelling species. The species tolerates pH 6.0-8.0, a hardness of about 2-25 dGH and a temperature of roughly 22-26 degrees C (Wikipedia); for spawning, soft water at the lower temperature end is appropriate.

Spawning Behavior & Trigger

The female holds 2-4 eggs between her pelvic fins, where the male fertilizes them for about 30 seconds; she then swims to a suitable spot and attaches the very sticky eggs. The pair repeats this process until approximately 100 eggs have been fertilized and attached, with eggs laid in dense vegetation and no parental care given afterwards (Wikipedia). The dense planting gives the female ample anchoring sites across the spawning session.

Egg & Fry Care

Because the adults give no parental care and Corydoras readily eat eggs, removing the parents or transferring the eggs protects the clutch. The fry hatch within about 4-6 days (Wikipedia); once free-swimming they accept small first foods such as microworm and newly hatched brine shrimp, and benefit from a thin sand layer and frequent small water changes.

Common Challenges

Maintaining soft, clean water and protecting the adhesive eggs from the unguarding adults are the principal challenges. Fungus on unfertilised eggs and unstable water during rearing are the usual causes of loss, so hygiene through the egg and early fry stages is critical.