Breeding Sterbai Corydoras
Breeding Corydoras sterbai: an egg-depositing catfish. Sexing the rounder female, a cool-water-change trigger, the T-position, eggs on the glass and a 3-5 day hatch.
Overview
Sterbai Corydoras (Corydoras sterbai) is an egg-depositing catfish whose captive reproduction the KB record rates as intermediate. It is bred using the classic Corydoras method involving group conditioning and a cool-water-change spawning trigger.
Sexing
Females are noticeably rounder and broader-bodied than males, especially when full of eggs, and are often also slightly larger.
Conditioning
Maintain a ratio of around two males per female and condition the group on a varied diet of live, frozen and dried foods until the females fill out with eggs.
Breeding Setup
A breeding tank of roughly 18″ x 12″ x 12″ with sand, fine gravel or a bare bottom works well, with sponge or box filtration and clumps of java moss. Target a temperature of around 24 °C (75 °F) and pH 6.5; filtering water through peat or using RO water is recommended.
- Temperature: around 24 °C (75 °F)
- pH: 6.5
- Sex ratio: about two males per female
- Substrate: thin sand, fine gravel or bare
Spawning Behavior & Trigger
The spawning trigger is a large (50-70%) water change with cooler water, with increased oxygenation and flow, repeated daily until spawning occurs. During the T-position, the male grasps the female's barbels between his pectoral fin and body and releases sperm; the female then deposits eggs, typically one at a time, though up to four may be released. Eggs are usually laid on the tank glass, often in an area of high water flow.
Egg & Fry Care
Eggs hatch within 3-5 days. Once the fry absorb their yolk sacs they accept microworm and brine shrimp nauplii as first foods, and develop better over a thin layer of sand than in a bare-bottomed setup.
Common Challenges
Getting the water soft and acidic enough, and timing the cool-water-change trigger when females are visibly full of eggs, are the main hurdles.