Breeding / Egg scatterers

Egg scatterers · Easy

Breeding the bronze corydoras

Eggs are usually laid on the aquarium glass; spawning is triggered by a large (50-70%) cooler water change, ideally with about 2 males per female.

Full species page

Step by step

Pairing

Keep a group of 6 or more with extra males. Females are rounder and larger.

Breeding tank

A 10-20 gallon (40-75 L) tank with fine sand, plants and a sponge filter. Add a spawning mop or plants. 22-26 C.

What starts it

A big cool water change (rain simulation) after a few days of rich food.

Eggs and young

Up to about 200 eggs per spawning; eggs hatch in 3-4 days (about 5 days at 22 °C).

Raising the fry

Feed microworms and baby brine shrimp. Remove eggs to a hatch tray to avoid egg-eating. Fry grow quickly.

Common mistakes

Not doing cool water changes
Leaving eggs with adults
Using sharp gravel

Setup blueprint

Home setup

One breeding tank for the bronze corydoras, drawn to scale from the breeding guide.

Breeding tank: 40 L · about 50 × 25 × 30 cm, 40–75 L from the breeding guide
Sponge filter and air pump · named in the guide
Heater, 22–26 °C · temperature from the breeding guide
Spawning mop · named in the guide
Plants for cover · named in the guide

Water: 22–26 °C · pH 6–8 · sand bottom

A plan from the breeding guide and an adult size of 7.5 cm. Tank shape is a standard 2 : 1 : 1.2 box, at least 6 adult lengths long. Check each step in the guide above.

Setup blueprint

Business setup

A 120 cm rack for breeding the bronze corydoras in numbers.

2 breeding tanks, 40 L each · about 50 × 25 × 30 cm, set up like the home tank
2 grow-out tanks, 80 L each · about 65 × 30 × 40 cm; twice the breeding tank, never smaller than this species' smallest tank
Shared air pump and air line · one line along each shelf feeds a sponge filter in every tank
Heat the room or each tank · 22–26 °C

In total: 4 tanks, about 240 L of water. A litre of water weighs about 1 kg, so check that the floor and rack can take the weight.

Sizes are worked out from the breeding tank in the guide. Tanks fit a standard 120 cm rack when they can; bigger tanks go on their own stands.

Male or female

Females grow larger and are rounder and broader-bodied than males, especially when full of eggs; easiest to see from above.

Can I breed it in my tank?

Your tank (litres of water)

Use a separate small tank with a sponge filter and spawning mops, so the eggs aren't eaten.
Good for a first breeding project.

Day-by-day plan

Typical for egg scatterers

Spawning date

14 days beforeCondition the parents
Feed live or frozen food twice a day. Keep males and females apart if you can.
Day 0Spawning
Eggs are scattered over mops or fine plants, often at first light. Remove the parents straight after.
Day 1Eggs hatch
Most eggs hatch in 1–2 days. Keep the tank dim and remove white (fungused) eggs.
Day 4Free swimming, first food
Fry use up the yolk and start swimming. Feed infusoria or liquid fry food several times a day.
Day 8Baby brine shrimp
Switch to newly hatched brine shrimp or microworms. Start small, daily water changes.
Day 21Crushed flake
Add finely crushed flake. Sort fry by size so the big ones don't eat the small ones.
Day 60Ready to move
Most small fish reach about 2 cm in 2–3 months and can join the main tank.

A general guide for this breeding type. Days change with temperature and species.

Simulator: guided

Stage 1 of 7Condition the parents

Feed live or frozen food twice a day. Keep males and females apart if you can.

Simulator: try it yourself

Set up a virtual breeding tank and see what would likely happen.

Temperature: 24 °C

Condition with live or frozen foodBig, cool water changePlants, mops or a breeding boxRemove the parents after spawning

No spawning

Without live or frozen food the parents aren't in breeding condition.
Corydoras usually need a big, cooler water change (like rain) to start spawning.

An educational estimate from the breeding rules, not a promise.