KOI FAQ: 18 Things to Know

What are Koi fish? These beautiful, colorful freshwater fish originate in East Asia. They come in a huge range of colors and sizes and can be used to create stunning ponds for your backyard or garden. But before you buy one, there are some things that you need to know to ensure that they live happily for years. Let’s take a look at 18 questions most people have about Koi Fish!

How Expensive Is a Koi?

Conventional domestic koi fish cost around $5-50 each, though some highly bred koi fish will average around $100 or so depending on the current market demand for them. You can get a good collection from a pond supplier without breaking the bank.

Some collectors spend dramatically large sums on their fish, however. According to Business Insider, the winning fish of 2017 All Japan Koi Show sold for $1.8 million!

Are Koi Fish Good Pets?

Koi fish are excellent pets, though they’re usually kept in outside enclosures. Those that come from healthy stock are highly intelligent and often prove to be really interesting to watch.

Why Are Koi Fish So Special?

Since koi are cold-water fish, they can adapt to a wide variety of climates, which helps them live all over the world. Few other domesticated fish are this hardy.

Due to carefully selected breeding, koi fish have scale patterns that resemble the look of delicate silk brocades. This visually distinctive style has kept them perpetually popular.

How Do You Tell If a Koi Is Male or Female

Male koi fish have this distinctive torpedo shape and tend to be very slender while females are generally larger. Their fins are also a different shape than males.

Adult male koi end up with small pointed fins that are solid in color. Some might even look completely opaque.

What Is the Rarest Koi Fish?

Ki Utsuri is the rarest koi fish by far. These have an extremely distinct color combination that consists of a dark lacquered-looking body that hosts yellow splotches.

They once almost went extinct, though it’s popular to produce a Ki Utsuri fish by breeding Magoi and Ki Bekko koi fish together.

Do Koi Like Music?

Fish don’t hear the same way people do, since sound waves travel differently through water than they do air. Koi tend to like peace and tranquility and may not appreciate music the same way that humans do.

That doesn’t mean you shouldn’t sit there and talk to your koi, however, because they’ll appreciate the company.

Can You Have Just One Koi Fish?

Some enthusiasts will keep a single koi fish in a 250-gallon pond. While it’s safe to keep just one koi fish in this way, adding more than maybe two into a pond of that size will potentially make them feel pretty cramped.

Owners of a single koi fish will want to make sure that they don’t overfeed their pond because it’s easy to do so with only one fish dining in it.

Can Koi Recognize Their Owners?

Once they’ve gotten used to their owners, koi fish might actually come up to the top of the pond to greet them. Some koi will even breach the water as a way of saying hello.

Eventually, socialized koi will also form gregarious bonds with the other fish in their pond. They’re surprisingly friendly and form communities in ways that much other domesticated fish won’t.

What Color Koi Is Most Expensive?

All of the extremely expensive koi sold at auction have been red and white thus far. The most expensive tend to have white areas that are silky white rather than bleached-looking.

They also tend to be completely free from blemishes of any other colors.

Is a Koi Fish Japanese or Chinese?

Modern koi fish were domesticated in 19th century Japan. Some forms have been kept as pets in Japan since around the 8th century according to Nihon Shoki, which is a period contemporary text on the subject.

An earlier form of domesticated Amur carp is from China, though it was actually raised for food as opposed to being kept as a pet.

What Eats a Koi Fish?

Raccoons, egret birds, snakes, domestic cats, and hawks will eat koi straight out of a pond if they’re allowed to do so. Owls and sometimes even pet dogs might snatch a koi fish if they’re moving around a lot, though they might not like the taste of it.

Catfish that are introduced to a pond could grow large enough to eat koi, as can any other large fish.

Do Koi Eat Other Fish?

Guppies and minnows are especially attractive to koi fish, and it’s almost a sure bet that they’ll eat them if they live in the same pond. They might sometimes eat mollies and fancy goldfish as well.

Over time, koi fish that share ponds with a catfish or fry might also eat these fish if they’re small enough.

Will Big Koi Eat Little Koi?

Mature adult koi might sometimes swallow little koi up, especially if they’re juveniles that are considerably smaller than they are. In general, you don’t want to mix different size fish to prevent this from happening.

When koi aren’t fed all that well, the risk that they might eat another fish in the pond they’re living in goes up dramatically.

Koi Fish Full Size

Butterfly and longfin koi can grow as long as 36-40″ while most other varieties will reach 24″ at most. An average koi can be anywhere from 12-16 lbs. in weight when fed well, though the largest varieties can approach 20 lbs. if they get enough food.

Can Koi Fish Live With Other Fish?

Several types of fish, most notably bottom feeders, make good pond mates for koi. Consider something like a barbel fish if you want to introduce other fish into a pond because they’ll help to keep it clean with their feeding activities.

How Often to Feed Koi Fish?

As soon as your pond is up and running, you’ll want to add easily digestible food around 1-2 times a week. During the winter months, you’ll probably need to cut back on feeding the fish considerably as they enter into a hibernation state.

Are Koi Aggressive?

Personalities differ between fish, but most koi will not be aggressive toward each other if they’re raised together and they have a big enough pond to swim in. They tend to get more aggressive if they don’t have a sufficient amount of space or food for one another.

Average water conditions generally permit around an inch of fish for every 10 gallons of water you have. Since each koi could be around 20″, that means you’ll want around 200 gallons for them.

Koi Live Webcam

Check out this live koi pond stream from San Diego (link to the webcam).