Breeding Corydoras undulatus

Breeding guide for the Wavy Cory (Corydoras undulatus), a cooler-water subtropical Argentinian cory and T-position egg-depositor following the standard genus pattern.

Overview

Corydoras undulatus is a wavy-patterned cory from subtropical Argentina. As with related cool-climate corys such as C. gladysae and the well-known C. paleatus, it tolerates and benefits from cooler conditions than most tropical species. It is an egg-depositor; species-specific captive spawning data are scarce, so the standard Corydoras protocol is followed here.

Sexing

Throughout the genus, mature females are larger and noticeably rounder and broader across the body than males, an effect most visible when females are gravid; this is the practical sexing cue for the species.

Conditioning

Condition adults on a varied diet of live and frozen foods together with quality sinking dried foods. Cooler-water corys such as C. paleatus do well around 21-23 C, a useful reference for conditioning this subtropical species.

Spawning Behavior & Trigger

A common and effective trigger is a water change of 50 percent or more using pre-treated water about 3-5 C cooler than the tank, simulating the cool rain that prompts spawning in the wet season. The pair then adopt the 'T' position, in which the female presses against the male to collect sperm, cups one to four eggs in a pocket formed by her pelvic fins and swims off to attach them to a surface.

Egg & Fry Care

Eggs are deposited on plants, glass or other firm surfaces and receive no parental care. They may be left in the tank or moved to a rearing container, and the fry are started on fine powdered foods, microworm and Artemia nauplii.

Common Challenges

Maintaining suitably cool, clean water and assembling a properly sexed adult group are the main hurdles. As with other subtropical corys, sustained high tropical temperatures are best avoided.