Breeding the koi
Spawns in ponds in late spring and summer at about 18-25 °C, scattering sticky eggs onto plants or spawning ropes; males chase and nudge the female.
Step by step
Choose healthy adults with good lines.
Large ponds.
Warming water in spring.
Very many eggs: about 100,000-120,000 per kg of female body weight. Common carp eggs hatch in about 4 days.
Infusoria, then powder food. Cull heavily.
- Poor genetics
- Not culling
- Overcrowding
Male or female
Males are slimmer with larger pectoral fins than females; females are fuller-bodied.
Can I breed it in my tank?
- Use a separate small tank with a sponge filter and spawning mops, so the eggs aren't eaten.
- Takes some experience.
Day-by-day plan
Typical for egg scatterers
- 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
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.
- Without live or frozen food the parents aren't in breeding condition.
An educational estimate from the breeding rules, not a promise.