Corydoras nattereri Breeding Guide

How to breed the Blue Corydoras (Corydoras nattereri): cooler-water trigger, T-position, single egg (up to 4) on glass, 3-5 day hatch and fry care.

Overview

Corydoras nattereri, the blue cory, is an armoured catfish reaching about 2.6 inches (6.5 cm) standard length, occurring in coastal zones of southern Brazil between Espirito Santo and Parana, in small tributaries, creeks, flooded forest and sand banks (Seriously Fish). It is a hardy, peaceful egg-depositor with documented spawning behaviour.

Sexing

Females are noticeably rounder and broader-bodied than males, especially when full of eggs, and are often slightly larger (Seriously Fish). The difference is easiest to judge from above.

Conditioning

The species is omnivorous and easy to feed: a good-quality sinking pellet or tablet as a staple, supplemented with live and frozen foods such as Daphnia, Artemia and bloodworm (Seriously Fish). Conditioning females on this varied diet brings them into spawning condition.

Breeding Setup

A breeding tank of about 18 x 12 x 12 inches with sand or fine gravel, sponge or box filtration and clumps of Java moss is suitable. Target around 70 degrees F (about 21 degrees C) and a pH near 6.5 for spawning, within the species' range of pH 6.0-7.6 and 20-23 degrees C (Seriously Fish).

Spawning Behavior & Trigger

Perform a 50-70% water change with cooler water and increase oxygenation and flow daily until spawning. In the T-position the male grasps the female's barbels between his pectoral fin and body and releases sperm, which is thought to pass through her mouth and gills. She deposits a single egg, although up to 4 may be released, on the tank glass (Seriously Fish).

Egg & Fry Care

Eggs hatch in about 3-5 days, and the fry take microworm and brine shrimp nauplii as first foods (Seriously Fish). Protect eggs from the adults by removing the parents or transferring the eggs, and keep water clean and stable during rearing, ideally over a thin sand layer with frequent small water changes.

Common Challenges

Maintaining the relatively cool temperatures this subtropical coastal species favours, conditioning females, and protecting eggs from predation are the main challenges. Because its natural range lies in cooler coastal southern Brazil, it does not require tropical warmth and may fail to spawn if kept too warm. Egg fungus on infertile eggs and poor fry-stage water quality are the usual causes of loss.