The koi fish is an extremely popular ornamental variety of carp. Koi are prized for their colors, which can be found in a wide range of shades and patterns, as well as the large size they attain when mature.

Because of this koi breeding is very popular among hobbyists as well as experts.

Prices range from relatively cheap to really expensive – depending on the bloodline and color patterns.

Today we are going to talk about how you can do this yourself on a very small budget and you may even breed the next Koi Champion winner!!

Stage 1: Spawning Koi Fish

Spawning is where all of the work begins when raising baby koi. The first thing you will notice is the males will frantically chase the females around your pond.

Now is the time to either move these breeding fish to a dedicated spawning tank.

Make sure you have plenty of room in whatever tank or holding area you choose as the fish need room to swim about and breed and add air stones to keep the water oxygenated.

koi fry breeding

The other option is to add spawning mops to your koi pond. These are called mops because they are made of multiple strands of fine nylon or synthetic material – similar to a mop.

Once the fish spawn the eggs will stick to anything they touch, and by adding a dedicated spawning mop you have the option to remove the eggs from the main pond before the other fish eat them all.

Once your koi fish spawn it’s time to remove the mops or mats from the main pond and put them into your fry tank or leave them in your spawning talk if you removed the breeding adults from your main koi pond to spawn. This is a great spawning brush

This doesn’t have to be anything special but use the same pond water as your main pond, maintaining the same temperature initially, and add some filtration and airstones.

Filtration is not really needed for the first few days because the current will potentially harm your baby fish.

Hatching Koi Fry

Within the first few days of hatching, your koi will be at their absolute most vulnerable. It is recommended you purchase an item known as a “spawn mop” or “spawn brush” to give the newborn koi fry a place to hold onto until they can begin to move about on their own.

spawning mop for koi carp

If you are serious about trying to breed koi you will already have these.

Once you move the mops to the new tank it’s time to start the waiting game.

Koi eggs about 5 days to hatch – depending on water temperature. Water temps can slow this process down but make sure that when you move the mops the temp is the same in your holding tank.

For the first day or two, baby koi pretty much look after themselves. They feed off their yolk sac but once this source of nutrition has depleted they are going to be looking for food. At this stage, they will have grown to about 7mm in size.

The koi fry starts to feed on infusoria in the water (microscopic creatures). and will do this for a couple of days. From this point on you can start feeding your baby koi.

What to feed Koi Fry

Once the koi fry starts to swim about freely you can start to introduce food to the tank. Brine shrimp are the best food for babies and the koi fry will gobble them up in the thousands.

I use Brine Shrimp as soon as the fry start to show interest. The will hammer them constantly once they get a taste for them. Here is a great kit to get you started.

Brine Shrimp for koi babies

Raising koi fry can be challenging if you are not prepared. If you go down the road of feeding the koi fry brine shrimp then you might be better off investing in a purpose-built hatchery.

They are relatively inexpensive and if you are serious about breeding koi it’s a great investment.

It’s like liquid food because you spoon it from your hatchery into the separate tank a few days after the eggs hatch.

Daphnia or ground-up fish flakes to make a fry powder are perfect food for baby koi fry. You can also grind up koi pellets and mix them with some fish flakes to create a tasty food source.

The fry will start to look a bit more like fish at this point and will be swimming about in the water properly.

Best Koi Fry Food

There are plenty of options available if you want to purchase fry food and here is a selection of the more popular shop brands on the market.

How much should I feed my koi fry?

Only feed enough that can be eaten within a few mins. When the koi fry are very young they only eat tiny particles of food. As they grow the amount of food should grow too.

Baby Koi everywhere

After another few days, you can start to see the eggs and fry that didn’t make it. The egg yolk will go a dull grey color and a number may start to grown a mold around them. This is common enough and an adult Koi can lay 1000’s of eggs.

A rough calculation of the surface area of your holding pond will tell you how many koi you can realistically manage and give the best chances to the stronger fish.

The sooner you can remove these dead koi eggs the better as you need to try to maintain water quality as best you can from the start.

Culling of deformed and sick baby koi is a must, and while off-putting to many if you go to the effort early enough it will help the survival of the overall batch. Some koi fish will be born with malformed fins and other babies will just not make it.

It is important to cull these fish as soon as they are born in order to keep the koi population within a manageable number.

If you don’t, it won’t be long before your holding area becomes overcrowded and all of the juveniles will die from lack of oxygen.

This is just the first stage in the culling process and you will need to do this again at about the 4-week mark. You need to select the strongest fish in the batch and ones that are starting to show interesting colors.

This is one of the challenges of raising koi fry and in our experience, you get the best results by culling fish without a decent pattern or stunted growth. This approach means only the best koi with the strongest growth end up in your pond.

How long do koi fry stay in the tank?

Realistically you are going to want to keep your fry in a separate location to the main pond for at least 4 months. If you add them any sooner they will possibly become food for your bigger fish.

It is at this point that you again need to sort out which fish to keep. Because the fish are stronger now and will have some interesting colors you can batch them up and give them to other pond enthusiasts or friends instead of culling them.

Whatever you do, make sure to not dump any fish into natural waterways as there are hefty fines for doing so – They are considered an invasive species and will harm the natural pattern of rivers and lakes if introduced.

You really only want to keep the best fish for your pond and get rid of the rest. Baby koi – like all koi fish grow into big adult fish over time so make sure your pond can accommodate the additional fish before you add them.

Moving your baby koi to the main pond

Now that the fry has grown in size you can start to think about moving them to the main pond. Treat this the same way you do when you add any new fish to your pond.

They should be bagged up with plenty of water and oxygen in the bag and placed on the surface of your pond to acclimatize. Give it about an hour and then you can release the fish into the pond.

Keep an eye on them for a few days until they settle down. You may notice that the newly introduced fish will shay away from the bigger koi fish in the pond. This is common enough so when feeding try and feed your main fish off to one side and then track back to the hideout of your smaller fish and give them some food as well – but make sure it’s the right size.

Huge koi in a 5000-gallon pond have very different eating habits to smaller types of koi fish so either use a different food or break up the pellets to suit.

Also, remember to keep an eye on your water parameters after you introduce the new fish. They will add to the overall load on the filtration system so frequent checks are necessary until everything settles down.

If you want to see Koi spawning in a pond then check out this great video. They go through everything from the initial showing of breeding to feeding the fry. Well worth checking out.

After everything settles down in your main pond you need to keep an eye on your water parameters.

The additional fish load will have an impact on water quality as the fish grow so make sure you have a pond filter that can cope with this additional load.

Why not take a look at our DIY Koi Pond Filter and see if this could work on your pond.