Dwarf Corydoras (Corydoras hastatus) Breeding Guide

Breeding the tiny Corydoras hastatus: sexing by body shape, a cool soft-water trigger, single-egg T-position spawning over several days, and rearing the small fry.

Overview

Corydoras hastatus is one of the smallest corydoras, growing to roughly 2.5-3.5 cm, and is unusual in spending much of its time in midwater among dense plants in large schools. It is an egg-depositing spawner that breeds following the typical Corydoras pattern.

Sexing

Females grow larger and become noticeably broader and deeper-bodied than males, while males are smaller and more slender with a more pointed dorsal fin.

Conditioning

Use a male-to-female ratio of at least two to one and condition the group well; this species suits cool, soft water for breeding.

Breeding Setup

Provide egg-deposition surfaces such as the aquarium glass, fine-leaved vegetation or sunken spawning mops, the mops being convenient for collecting eggs. A thin sand layer is preferred over a bare tank for raising fry.

Spawning Behavior & Trigger

Trigger spawning with large 50-70% water changes using cool, soft water while increasing oxygenation and flow, repeated daily until the fish spawn. In the classic single-egg method the female holds an egg between her pelvic fins where the male fertilises it for about thirty seconds; females lay roughly 7-15 eggs per day over three to four consecutive days, totalling about 30-60 eggs.

Egg & Fry Care

After spawning, remove either the adults or the eggs; many breeders add a few drops of methylene blue or an alder cone or two to prevent the eggs developing fungus. Eggs hatch in around three to nine days, and once the fry absorb their yolk sacs they take small live foods such as microworm and Artemia nauplii. Rearing over a thin sand layer with excellent water quality improves survival, and the young mature in roughly six to eight months.

Common Challenges

The very small fry are delicate and need suitably tiny first foods and clean water, so the rearing phase is the most demanding part of breeding this species.