Corydoras zygatus Breeding Guide

Breeding the Black-Band Cory (Corydoras zygatus): sexing, conditioning, a cooler water-change trigger, T-position spawning and raising fry.

Overview

Corydoras zygatus, the Black-Band Cory, is recorded from the Ucayali, Huallaga, Santiago and Pastaza river systems of eastern Ecuador and northern Peru, growing to 60-70 mm; FishBase places it in the western Amazon basin (now also treated as Osteogaster zygata) and lists it as Least Concern (2020). It closely resembles C. rabauti and spawns in the genus's typical T-position.

Sexing

Seriously Fish states that females tend to grow larger and that sexually mature individuals are noticeably broader and deeper-bodied than males.

Conditioning

Condition the group on a varied diet of live, frozen and dried foods until the females fill out with eggs. Seriously Fish recommends keeping two or more males per female where possible.

Breeding Setup

Seriously Fish reports maintenance parameters of 20-26 degrees C, pH 5.5-7.5 and hardness 36-215 ppm. Provide good filtration and somewhere for eggs to be laid, such as aquarium glass, fine-leaved vegetation or sunken spawning mops.

Spawning Behavior & Trigger

Trigger spawning with a large 50-70% water change using cooler water while increasing oxygenation and flow, repeated daily until the fish spawn. Eggs are deposited on the aquarium glass, among fine-leaved vegetation or within sunken spawning mops in the genus's T-position; after spawning, remove the adults or the eggs.

Egg & Fry Care

Seriously Fish gives an incubation period of normally 3-4 days. Most breeders add a few drops of methylene blue or an alder cone or two to prevent the eggs developing fungus. Once the fry have fully absorbed their yolk sacs they accept small live foods such as microworm and Artemia (brine shrimp) nauplii, and require excellent water quality.

Common Challenges

Fry do better over a thin layer of sand than in a bare arrangement. Fungused eggs and poor water quality are the usual causes of losses, so keep the eggs and fry clean and well-oxygenated.