Can Koi and Goldfish Live Together?

If you already have an established pond and are looking at mixing some different species into it for more variety then you may well be wondering can koi and goldfish live together in harmony?

Yes koi and goldfish can live together in the same pond or tank providing that the goldfish are big enough, there is enough space and food for both species.

If you are planning on adding koi to a goldfish tank then you might want to reconsider as koi require a lot more space than goldfish.

While you might think you have a large tank already the space requirements of a koi vs goldfish is quite large so please bear that in mind.

Can Koi and Goldfish Live Together?

Yes both goldfish and koi will live together happily providing that there is enough food available, they are not overcrowded and the goldfish are of a big enough size so that the koi do not eat them.

Both species prefer the same type of pond or tank and are happy to live at the same pH and water temperature levels.

Mixing goldfish and koi together can result in a much more visually appealing pond as the variety of sizes and colors will really improve the visual appeal of the pond.

1. Sizing

Assuming that you have a big enough pond with plenty of space already for your existing fish then your koi should be able to share with goldfish providing that the goldfish are of a big enough size so that the koi will not eat them.

Larger, more mature koi will eat other fish and goldfish in particular as they are quite docile.

Koi will grow to a much larger size than goldfish so adding the goldfish in when the koi are young will mean that as both species age the goldfish will have a much better chance of reaching maturity.

Some people do keep koi fish in tanks but the tanks need to be extremely large so the best place to keep them is in a pond.

If you start adding goldfish to a tank you may find that within a few years your tank is too small for both fish and you’ll have to make a difficult decision to keep and upgrade your tank or to get rid of some of the fish.

2. Sufficient Food

Making sure that your goldfish are getting enough food is one of the biggest concerns as koi eat a lot and if they are larger and older than the goldfish that you intend on adding to your koi pond then you need to make sure that your goldfish will not get bulled out of the way by the koi.

Spreading your food out over a larger area is one way to ensure this as it gives all fish in the pond the opportunity to feed.

Also Read: What Do Koi Eat?

They should be closely monitored at feeding time to ensure all fish are receiving the food that they need.

More fish means more food which will also lead to more waste in your pond or tank so you will also need to monitor the quality of your water carefully.

3. Overcrowding

Having too many fish in your pond or tank will result in some of the fish dying prematurely and the chances are the goldfish will be the first to die while the larger koi will survive.

As mentioned above koi need a large pond in which to thrive and if you start to introduce other fish this space will start to diminish over time.

Most ponds will not or cannot be enlarged once they are built as the cost is either to great or there is not enough room to spare.

Therefore you need to look several years ahead to see if the amount of koi and goldfish can live together once they have several years of growth added to their size.