Koi Fish vs Goldfish: Which Is Best for a Pond?

Posted by on 08/11/2023

Some of the most popular fish for a pond include Koi and Goldfish, but both are two distinct species with very different care requirements. If you're in the process of stocking a pond, or you're just curious to know the differences between the species, you've come to the right place!

In this post, we'll compare Koi and Goldfish so that you can decide which fish you like best, and which might be the better choice if you decide to add them to your backyard pond.

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Koi Fish

Koi, also known in Japan as Nishikigoi, are color variants of the Amur carp. Through centuries of crossbreeding, Koi have been bred to produce a wide variety of colors and different patterns. Koi fish are incredibly long-lived, and have an average lifespan of 25-30 years, with some species living for up to 60 years.

The species is quite popular among hobbyists, largely due to their aesthetic appeal. Their bright colors are easily viewable from above, making them a popular choice for ponds. They're incredibly hardy fish and can live comfortably in the winter. Due to being cold-blooded fish, they're able to slow down their metabolism and survive throughout the cold winter months. Koi are known to grow to be quite large, and adult Koi can reach a maximum length of around 3 feet!

Image of multiple Koi swimming in a pond
Koi can live for up to 60 years


Similar to Koi Fish, Goldfish are also capable of surviving a wide variety of temperatures. They are frequently chosen as pond fish and are also pursued for their hardiness and bright colors.

Native to China, goldfish are members of the carp family and have been bred for thousands of years. The species is quite personable, as they can even recognize their owners. In a pond environment where they're well-fed, these fish can easily reach over a foot in length. Similar to Koi, they are also long-lived, with a lifespan of about 20 years.

Image of Red Oranda Goldfish in a pond
Red Oranda Goldfish swimming in a pond

Best for Hobbyists on a Budget

Building a pond is no easy feat and you'll need to purchase quite a few things to make it happen. We recently provided some guidance in a related post by RedFin 10 Steps and Considerations For Building The Perfect Backyard Koi Pond .

Koi fish can be quite expensive, and for those looking to cut some costs, a backyard pond with Goldfish is a more affordable option. A single Koi fish can cost hundreds of dollars, while a Goldfish suitable for a pond will range from $20-$100 per fish.

Best for Small Ponds

If you're planning on building a smaller-sized pond, Goldfish are the way to go. Goldfish only require a pond that's at least 50 gallons in size and 4 feet deep. 

For hobbyists with a pond between 50-500 gallons, Goldfish are the best choice to build a beautiful backyard ecosystem.

Best for Large Ponds

If your pond is over 1000 gallons, you meet the minimum size to keep Koi. Hobbyists with large ponds and money to spend are eligible for a Koi pond, so why not take the plunge?

Owning Koi is an incredibly rewarding experience, and in Japanese culture, have even been known to bring prosperity and luck to their owners!


As you can see, both Goldfish and Koi fish are ideal candidates for a backyard pond. In most cases, the size of the pond, and the hobbyist's budget will be the deciding factor on which species is the better choice.

Now that we've covered these two different types of fish, which do you think you'll choose? Both options are aesthetically pleasing and easy to take care of, and we guarantee you won't regret maintaining either species. And if your budget allows - why not keep both? These fish can live together comfortably, just make sure you have a pond that's large enough!

Image of Miles Harrison

Miles Harrison

With over a decade of aquarium experience, Miles can be found writing about saltwater and freshwater aquariums. When he’s not writing about fish, you can find him going for a run or building websites, such as this one!