Bluespotted Corydoras (Corydoras melanistius) Breeding Guide
How to breed Corydoras melanistius: 2:1 sex ratio, cooler-water trigger, T-position spawning, eggs on glass, hatch in 3-5 days, fry on microworm and brine shrimp.
Overview
Corydoras melanistius occurs in Guyana, Suriname and French Guiana and reaches about 5.5 cm (2.2 inches). It is an egg-depositing catfish bred using the classic Corydoras method of a cooler-water change to trigger T-position spawning.
Sexing
Females are noticeably rounder and broader-bodied than males, particularly when carrying eggs. The difference is most visible when the fish are viewed from above.
Conditioning
Condition the fish on a varied diet of live, frozen and dried foods, using a ratio of two males per female. Keep them within the species range of 22-26 degrees C (72-79 degrees F), pH 6.0-7.0 and a hardness of 2-15 dH.
Breeding Setup
A breeding tank of around 18 by 12 by 12 inches works well, with a bare bottom, sand or fine gravel substrate. Eggs are generally laid on the aquarium glass.
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. During the T-position the male grasps the female's barbels between his pectoral fin and body and releases sperm toward her pelvic fins; she forms a basket to deposit single eggs, with up to 4 released at a time.
Egg & Fry Care
Eggs hatch in 3-5 days. Once the yolk sacs are absorbed the fry accept microworm and brine shrimp nauplii as first foods, and they appear less susceptible to disease when kept over a thin layer of sand.