Corydoras rabauti Breeding Guide

How to breed the Rust Corydoras (Corydoras rabauti): sexing, conditioning, a cooler water-change trigger, T-position spawning and raising the fry.

Overview

Corydoras rabauti, the Rust Corydoras, is a callichthyid catfish recorded from the Rio Javari on the Brazil/Peru border and likely Colombia, reaching about 55-65 mm. According to Seriously Fish it has been bred in aquaria; like other members of the genus it is an egg-depositing spawner that uses the characteristic T-position. The notes below summarise the documented spawning protocol for this species.

Sexing

Seriously Fish states that females tend to grow larger and that sexually mature individuals are noticeably broader and deeper-bodied than males. The difference is clearest when females are full of eggs, viewed from above.

Conditioning

Condition a 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 to improve the chance of a successful spawn.

Breeding Setup

Seriously Fish reports maintenance temperatures of 20-27 degrees C, pH of 5.5-7.2 and hardness of 18-215 ppm for this species. Provide good filtration and somewhere for eggs to be laid, such as aquarium glass, fine-leaved plants or sunken spawning mops; mops are recommended because they make egg removal easy.

Spawning Behavior & Trigger

To trigger spawning, perform large 50-70% water changes with cooler water while increasing oxygenation and flow, repeated daily until the fish spawn. Spawning follows the genus T-position: the male grasps the female's barbels while she forms a basket with her pelvic fins, into which a small clutch of eggs (typically a single egg, though up to four can be released at once) is deposited and then attached to a chosen surface.

Egg & Fry Care

Seriously Fish gives an incubation period of roughly 3-4 days. Many breeders add a few drops of methylene blue or an alder cone to the hatching container to discourage fungus. Once the fry have fully absorbed their yolk sacs they accept small live foods such as microworm and Artemia (brine shrimp) nauplii.

Common Challenges

Seriously Fish notes the fry are not the easiest to raise and require excellent water quality; they fare better over a thin layer of sand than in a fully bare arrangement. Fungused eggs and poor water quality are the most common causes of losses.