Can guppies live with koi?

If you envision your koi pond eventually taking on other fish then maybe pairing guppies and koi together may be one thing that you considered. Is that a good idea though?

So, can guppies live with koi? In my opinion no, because koi get very large. Koi carp are likely to grow 5x the size of guppy and will probably eat them. Guppies can also transfer disease and give the koi ulcers on their scales. If you want guppies, I would have them in a different pond or water system.

Why Are Guppies So Great?

Even though a guppy is really small it is tough too. It can withstand pretty extreme temperature fluctuations that are outside of their comfortable internal temperatures. Keep the pH of the pond in balance though at around 7-8 or there will probably be problems.

In addition to being hardy, guppies keep your pond cleaned out of algae and mosquito larvae so they help the habitat thrive. I don’t know of anyone who likes mosquitos flying about unchecked. Yuck!

The small size of guppies, the small amount of food required, and the fact that they love eating things that are pests make them a great fish for beginning pond fish enthusiast. Notice I didn’t say anything about adding koi to the mix. There is a reason.

Do Koi Eat Guppies? 

There are some instances where I heard people adding guppies to their swimming pet collection along with koi and things turning out fine. Koi have been bred over centuries to be more docile than their wild carp cousins.

They are generally considered as gentle giants who get along fine with other wildlife in their habitats. They are, however, also opportunistic omnivores who will eat other smaller fish including even their own babies, or fry, if their dietary needs aren’t being met elsewhere. So feed them on a regular basis if they are around minnows or guppies especially. 

Is There Hope For Getting Koi and Guppies To Get Along?

I think the risk is too high generally to put guppies in a koi pond. You will have situations where you have to be away from your pond for a while and your koi will run out of food. If there aren’t enough bugs or plants about then they will consider their other food sources in their watery homes.

However, I visited this forum, and a visitor named Kahhoe and another named nivek say their koi and guppies get along just fine. Plenty of other people on that forum have very different stories too though. If you fast your koi, then they will eat guppies and guppy fry. As I said, they are opportunists that will eat what’s available.

Can koi live with other fish?

Size Matters

Guppy is very tiny at around 2.5 inches at adult size. Compare that to koi who can reach 3 feet, or 36 inches. Guppy must think there are whales in their waters. Some people have said their guppy fish have actually managed to develop their own habitats beside their koi companions though. That confuses me since koi seem to eat everything around in the Summertime.

The guppies are probably staying hidden inconspicuously in a corner out of sight of the koi in their pond habitat during Summer. If they make it to Winter, then that’s great for them because the koi go into hibernation in Wintertime and just can’t eat. 

There is also the problem with pathogens

You might also get illnesses from the guppies passed on to the koi. Koi are supposed to be pretty and show-worthy fish. The vibrant colors will dull out quite a lot if they come in contact with pathogens in the water and start to have ulcers develop on their scales.

You then need to go through the trouble of removing your koi from the water and need to move them to a quarantine tank. Another hassle you might avoid if you just keep only koi in your pond. Let your other fish be part of an aquarium or something

Fish You Can Stock With Koi

There are better options than guppy to stock your koi pond. Regular goldfish is a good option, but not the fancy type of goldfish that are smaller. Regular goldfish are too large for koi to eat. They might mate together to make crossbreeds. These cross-bred fish are born sterile though, meaning they can’t reproduce.

Another great fish to pair with koi are Golden Tenches. I like the other term that they are called, “Doctor Fish”. This is because they have a protective skin that has a powerful antibiotic that prevents many fish-related illnesses. That is great for koi because of their disease-proneness.

In addition, these tenches eat the excrement of koi too. They seem like the perfect partners to koi for these two reasons. Bear in mind these fish are bottom-dwellers so once you put them in your pond you probably won’t see them very much. They will be working in the bottom of your ponds habitat keeping thing nice and tidy. They work better as a group of 5 or 6.

Ide(Orfe) fish are another type of fish that can mingle with koi because they can get to lengths of 24 in. Like koi, they are visually appealing and love to surface often. This makes them a very popular pond fish for those who want a visually appealing pond.

Some people have made water sanctuaries that let koi, goldfish, and guppy live in harmony, or it looks that way according to this peaceful video below. I still think koi and guppies don’t make good playmates due to the possibilities of koi getting ulcers from disease the guppy spread and the koi potentially eating guppies. Sounds like each ain’t good for the other.

The Final Verdict:

There is a fairly good-sized list of fish that would be perfect for keeping in your pond, but as you learned many aren’t ideal if koi are involved. No guppies, minnows, betas, or other smaller fish should be kept in your pond due to the high risk of being eaten.

For all these different fish make sure you have quality water that is filtered and clean. Koi and other fish who like to surface are inviting to predators so pond netting is also a good idea or they won’t last long. 

Can guppies live in a pond? Yes, they can. Guppies are more into tropical temperatures, but they can do ok in water anywhere in the range of 55-86°. They are hardy survivors and right at home eating up mosquitos and their larvae. 

No more OFF repellent needed! One study a while ago found that water systems that had guppies in them found 30% less mosquitos after the guppies had only been in the water for a month than those without guppies.

Can koi live with other fish? Fish make your pond have some character. If you have koi then you might be tempted to add other fish. This is fine as there are some species of fish that make great companions like the Golden Tenches mentioned above. 

Regular goldfish are not only attractive but are on par with koi as far as size is concerned with koi being about a foot longer on average. So yes koi can live with some other fish. Just make sure you don’t pick a species that your koi might harm and vice versa.

Do koi eat other koi? Yes, they do. Koi are known for eating their own fry and the survivors are just the ones who manage to drift out of eyesight of their parents. I don’t know how it is that any of them survive, but they do. 

Once they get to be even an inch long though their bigger koi brethren actually see them as koi. The whiskers and other indicators of a koi have grown in and they become part of the koi social circle. But yes koi definitely do eat other koi if they haven’t grown enough.


Top Image: Schumi4ever [CC BY-SA 4.0], via Wikimedia Commons and modified to be smaller than actual image with text added.

Photo by Denis Lesak on Unsplash

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