Breeding Corydoras guapore

How to breed Corydoras guapore: sexing, a cooler water-change trigger, glass and spawning-mop egg deposition, and raising fry.

Overview

Corydoras guapore (now also placed in the genus Gastrodermus) is an armoured catfish of the family Callichthyidae native to the Rio Guapore basin on the Brazil/Bolivia border, within the upper Rio Madeira system. According to Seriously Fish it reaches around 40-50 mm standard length and is unusual among its relatives in forming midwater aggregations. It is reported as rarely bred in aquaria, though when successful the method follows the general Corydoras pattern.

Sexing

Females tend to grow larger, and sexually mature individuals are noticeably broader and deeper-bodied than males, a difference that is easiest to judge when the fish are viewed from above.

Conditioning

Condition the breeding group well before attempting to spawn them; a varied diet supports egg production in females. A ratio of two or more males per female improves the chance of successful fertilisation.

Breeding Setup

FishBase lists a broad environmental tolerance of pH 6.0-8.0 and a temperature range of about 21-24 C for the species. Fry are reported to fare better over a thin layer of sand rather than in a bare arrangement, so a shallow sand layer is preferable to a fully bare base.

Spawning Behaviour & Trigger

To trigger spawning, perform a large 50-70% water change with cooler water and increase oxygenation and flow in the tank. Repeat this daily until the fish spawn. As in other members of the genus the female cups the eggs and deposits them at a chosen site.

Egg & Fry Care

Eggs are laid on the aquarium glass, among fine-leaved vegetation, or within sunken spawning mops; mops make egg removal easier. Methylene blue or alder cones are commonly added to reduce fungal infection. Incubation is normally 3-4 days, and once the fry have fully absorbed their yolk sacs they accept microworm and Artemia (brine shrimp) nauplii. Fry require excellent water quality.

Common Challenges

This species is rarely bred in aquaria, and fry demand consistently high water quality. Keeping the young over a thin sand layer is reported to reduce losses compared with a bare tank base.