Koi are about 10 inches (25 cm) long when they are 3 years old. [1] X Research source
It is easy to spot males once they start breeding as they will chase the females around the pond. [2] X Research source It is safe to have multiple male koi in the same pond.
If you are looking for a certain color, choose koi parents that demonstrate that coloring. Avoid using a child’s pet koi for breeding as the koi can suffer torn fins, bruises, cuts and occasionally death, during the breeding process. Take your koi to a vet if you are worried about their injuries.
If you don’t have the right conditions or enough capacity for baby koi, consider removing the males from the pond during this season. You will need a pond that is 3 feet (0. 91 m) deep and 6 feet (1. 8 m) by 8 feet (2. 4 m) foot wide to house 5 koi. For more koi, you will need a larger pond.
Pond filtration systems can be purchased from pet stores or specialty fish shops for between US$200-US$2000. If your pond is particularly dirty or filled with algae, you may need to completely clean it out.
Skimmer nets can be purchased from DIY stores. If cats or birds are approaching your pond, cover the pond with netting to protect the koi. Use a piece of netting that is large enough to cover the pond and secure it down with heavy rocks.
Increase the amount of protein you feed your koi, as this helps support their bodies for breeding. Protein supplements can be purchased from a pet store. Follow the feeding instructions on the back of the packet.
Purchase a fry mat from a pet store or a specialty fish shop.
If you are wanting to breed a small number of koi, leave the adults in the pond. Purchase a koi tank from a pet shop. For 2 koi, you will need an aquarium that is at least 100 gallons (380 L). [3] X Research source
Once the koi have mated, you will see a froth appear on the top of the water and their eggs will be visible on the fry mat.
The eggs will hatch after about 4 days. If you are breeding the koi for profit, remove the parents out of the pond as soon as you notice the eggs or the presence of froth on the water.
Continue to feed the baby koi powdered food until they are 4 weeks. Over time, you will learn how much food the baby koi will eat during each 5-minute feeding session. It can take a few days for the koi to get used to eating the powdered food. Feed the fish 10 days after you notice the eggs.
Make sure that the koi are culled humanely. You don’t necessarily need to dispose of the koi. Consider giving them away to friends or family members if they are healthy. Koi can be culled at any age, although, it is best to wait until their patterns emerge so that you can choose to keep the koi with your favorite colorings.
Baby koi take approximately 3 months to reach 3 inches (7. 6 cm).
