Koi Fish in a Pond at Sunset

The 10 Best Fish Types for Koi Ponds

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An outdoor pond can make any backyard stand out. While the flowing water and surrounding plants bring some solid visual appeal, the main highlight of a pond is seeing the fish swimming and interacting. If you like the idea of having your own koi pond, it’s important to figure out which fish species can thrive in it. There are various aspects to consider when deciding on the right fish to add to your pond. You should take into account the pond’s dimensions as well as the climate in the area.

While outdoor pond conditions can differ from one backyard to another, it’s very important to be careful about the type of fish chosen. It’s safe to say that some species have a much higher survival rate in a backyard pond than others. If you wish to enjoy a beautiful koi pond in your yard with fish thriving for years, check out the best options. We’ll take a close look at the ideal fish to stock a pond with.

1. Koi

Koi Fish in a Pond

Koi fish is the traditional choice for many outdoor ponds. It makes sense to get koi if you’re planning on setting up a koi pond in your yard. Koi fish feature solid ornamental potential while their natural hardiness increases survivability in case of temperature fluctuations. Koi carps are coldwater fish originally from Japan. They show off a wide range of colors decorating their graceful cylindrical bodies.




Compared to other types of fish that do well in an outdoor pond, koi can be considered quite expensive. However, these fish are a great investment considering their extended lifespan. Just make sure you provide them with a suitable enriched diet. Koi fish need a sufficiently large and deep pond to thrive. Depending on the number of included fish, you will typically need an outdoor pond with a capacity of over 1000 gallons of water.

2. Goldfish

Goldfish in a Pond

While goldfish are usually associated with aquariums, it might be surprising to find out that this is a suitable type of fish for outdoor ponds. The fish can handle cooler waters better compared to other tropical species. There are lots of different types of goldfish to choose from for stocking the pond. The fancy goldfish is a notable example because it brings a distinctive flair with its vibrant appearance.




Due to their smaller size, goldfish don’t need a very big pond to thrive. However, it’s recommended to provide around 20 gallons of water for each fish added. Goldfish aren’t as demanding as koi but still need a decent pond depth to allow sufficient swimming space. It’s a good idea to ensure an optimal water temperature. Shade could be required in warmer climate areas.

3. Mosquitofish

Mosquitofish in a Pond

Anyone who’s into pond fishkeeping has probably heard about the mosquitofish. It’s not a popular choice for aquariums but it’s a solid pick for stocking a koi pond. This is a small fish whose body resembles the shape of a torpedo. Mosquitofish are agile and pretty difficult to spot due to their dull coloration that allows great camouflaging in a pond environment.




There are lots of good reasons that make the mosquitofish suitable for ponds. Their looks might not be the most impressive but they bring other notable benefits. The name of the fish comes from its tendency to eat lots of mosquito larvae. That means you can count on mosquitofish to maintain your backyard pond pest-free. When it comes to adaptability, this type of fish can thrive in a wide range of pond conditions, including some environments experiencing temperature fluctuations.

4. Sterlet Sturgeon

Sterlet Sturgeon in a Pond

Due to a natural adaptation to cold water, the sterlet sturgeon represents a solid pick for outdoor ponds. This isn’t a particularly common pond fish but its resilient nature and unique appearance can make it worth considering. The only potential drawback is that sterlet fish require a specific diet. You can’t just use any typical commercial fish food available. Overall, it’s a pretty low-maintenance fish as long as you provide it with the right conditions to flourish.




Sterlets are an endangered species in the wild because of excessive fishing. If properly taken care of in an outdoor pond, you can expect this fish to live for more than 20 years without problems. It’s possible to keep sterlet fish together with other species such as koi. However, make sure they can be properly fed because sterlets are bottom feeders and can be easily outcompeted by the koi.

5. Guppy Fish

Guppy Fish in a Pond

If you have a small pond, your fish choices will be more limited. Consider the guppy fish that measures just two inches in length. It’s an ideal pick to stock a small pond, especially when you take into account its flamboyant looks. The female of the species is larger than the male but you will probably want to add males more because of their standout appearance.




Male guppy fish have an eye-catching tailfin decorated with vibrant patterns that are more striking than the one featured on the females. Another reason to consider the guppy fish for your pond is the impressive variety of colors and patterns. There are lots of different species to add some tropical vibes to any backyard pond. Keep in mind that you should only add guppy fish if you live in a warmer area.

6. Weather Loach

Weather Loach in a Pond

A common fish choice for keeping in manmade ponds, the weather loach is a bottom feeder that shows off excellent hardiness. You could say that it’s specially adapted to live in ponds because the weather loach is an old domesticated fish species. It’s even called the pond loach sometimes due to its popularity in this kind of environment. Weather loach fish will get along well with other peaceful fish.




The ideal environment for a weather loach should ensure an optimal water temperature between 40 and 77 degrees Fahrenheit. Weather loach fish can withstand winter conditions and tolerate temperature fluctuations quite well. The only notable consideration is that you should always stock the pond with more than one fish because it’s a very social animal.

7. Fathead Minnow

Fathead Minnow in a Pond

Great for smaller ponds, the fathead minnow has many attractive qualities including the ability to survive without the need for a pond filter. This is a freshwater fish that can easily tolerate low-oxygen water and more difficult survival conditions. Another interesting aspect of fathead minnows is that it takes minimal effort to breed them.




When it comes to appearance, the fathead minnow features light green or grey colors. Some variants offer a contrasting pinkish-orange. The fins of this fish stand out because they’re translucent and streamlined. These fish prefer insects and algae to feed on. They will maintain an outdoor pond clean to create a more welcoming environment for other fish.

8. Plecostomus

Plecostomus in a Pond

With a tiger-like appearance, the Plecostomus is an interesting fish for any koi pond. It’s part of the catfish species and it’s a native of South America. Plecostomus fish are nocturnal so they won’t be easily seen in daylight due to sitting concealed in the crevices of the pond. Basic outdoor ponds may not be suitable for Plecostomus fish. It can usually flourish only in larger ponds with some good hiding areas.




The main diet of the Plecostomus is algae. You shouldn’t have too many difficulties keeping this fish properly fed. Keep in mind that this is a warm-water fish. That means it should be considered only if you live in a warm climate area for an outdoor pond. Plecostomus fish prefer water temperatures ranging from 72 to 86 degrees Fahrenheit.

9. Molly Fish

Molly Fish in a Pond

The molly fish is instantly recognizable because of its common presence in aquariums. It features a flattened body with a triangular-shaped head. The fish has an eye-catching fan-shaped tail. When it comes to colors, there are different options available, depending on the exact species. Although molly fish are mainly used for aquariums, they’re also very suitable for outdoor ponds.




Keeping molly fish healthy is a breeze. This type of fish is recommended if you want a gentle pond fish that’s easy to maintain. It can handle most environments thanks to its natural resilience. Cold winters can pose some issues, however. Make sure the water temperature won’t drop under 75 degrees Fahrenheit. Molly fish breed quickly so it’s probably best to consider a larger pond for them.

10. Golden Rudd

Golden Rudd in a Pond

Also known as the rosette fish, golden rudd is another hardy fish that could be great for stocking a koi pond. It can survive winter conditions that would be deadly for other fish. With proper care, golden rudd fish should be able to live for up to 20 years or more. One advantage this fish has over others is the superior resistance to diseases. This could be an important factor for outdoor pond fish.

When it comes to appearance, the golden rudd shows a shiny silver body with distinctively vibrant orange fins. It’s recommended to keep these fish in groups of around 10 individuals. Rosettes require oxygen-rich water and efficient filtration performance to flourish. Consider bringing in some aquatic plants in your pond to keep these fish healthy.


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