Duplicate Corydoras (Corydoras duplicareus) Breeding Guide
Breeding Corydoras duplicareus, a soft blackwater cory: sexing, egg deposition on substrate or near the waterline, and the genus Corydoras cooler-water spawning trigger.
Overview
Corydoras duplicareus comes from the upper rio Negro system in Brazil and reaches 40-50 mm standard length. It naturally inhabits blackwater tributaries with tea-coloured water, low hardness and a pH of 4.0-6.0, and is an egg-depositing catfish.
Sexing
Females tend to grow larger, and sexually mature individuals are noticeably rounder and broader-bodied than males, especially when gravid.
Conditioning
Condition the group on a varied diet in soft, acidic water. Maintenance parameters for the species are a temperature of 20-26 degrees C, pH 4.0-7.0 and a hardness of 18-90 ppm, reflecting its blackwater origin.
Spawning Behavior & Trigger
This species is reported to deposit eggs either on the substrate or around the water line. As documented across the genus Corydoras, a large (50-70%) water change with cooler water, plus increased oxygenation and flow, is used to trigger T-position spawning, in which the male grasps the female's barbels and she forms a pelvic-fin basket to carry the eggs.
Egg & Fry Care
Following the genus pattern, eggs hatch within a few days and the fry take small live foods such as microworm and Artemia nauplii once their yolk sacs are absorbed. Soft, clean, slightly acidic water suits the developing fry.