Can You Keep a Koi Fish in a Fish Tank

Can You Keep a Koi Fish in a Fish Tank

Koi fish are known for quite a few different things. Their colors, their friendly nature, their rich history, and their massive appetites are just some of the things that people immediately recognize about these stunning animals. 

Still, there is one thing that is noticed above all else: their size. Koi fish are huge animals and grow incredibly quickly, reaching lengths of two to three feet in very short periods of time. 

This is why they are often kept in large ponds or custom built above ground enclosures. Still, some people have a strong desire to keep koi fish indoors.

Let’s take a look at if you can keep a koi fish in a fish tank and discuss the best options to ensure your fish have enough space to thrive and grow. 

The Problem With Indoor Koi Enclosures

Koi fish can survive in a lot of different conditions. They are very hardy fish who can handle a lot and still come out okay, if not a little worse for wear. 

That being said, they cannot thrive if they do not have the appropriate conditions to do so. 

This is why, in most cases, keeping koi in an indoor tank enclosure is not a good idea; it is simply very difficult to find an enclosure that offers them enough space to thrive and become the big, beautiful fish we know and love. 

Due to this, it is often easier and best to opt to keep your koi in an outdoor or indoor pond enclosure if possible. 

It can be tempting to keep koi fish in a fish tank but unless you have very specialized tanks available that can suit the size and growth of a koi fish, it simply is not feasible. 

This may seem strange considering koi fish are often kept in tanks by the dozens in many pet stores but this is because they move through stock quickly there, with koi being purchased often enough that the fish are not spending much time in the store tank. 

The unfortunate misconception that because the koi were kept in a tank in the store means they can be kept in one at home, as well, is one that plagues the koi keeping community and has caused the illness, stress, and even death of countless koi fish. 

When koi are small they can survive in a tank but since they grow very quickly, they cannot stay in a standard tank for long. 

A koi needs at least ten gallons per inch of fish, meaning that a koi that is an adult with a length of three feet, or 36 inches long, would need 360 gallons at the very least, though more is definitely better. 

This is for each fish in the enclosure, as well, meaning that if you have four fish and two are two feet long and two are three feet long, you would need 1,200 gallons to accommodate all of the fish in the pond. 

Since many ponds have much more than just four fish, you can imagine the issues that would arise with keeping multiple koi fish in a tank style enclosure. 

Koi Fish in A Fish Tank

Situations Where Koi Fish In A Fish Tank Is Acceptable

While tanks are not suitable for keeping koi permanently unless they are custom built to allow for adequate movement and proper volume, there are still quite a few reasons to keep a spare tank around. 

Koi fish sometimes cannot stay in their pond and having a cycled tank at the ready can help negate issues before they happen, saving you a lot of time and money. 

For example, when a koi fish is sick or a new fish is being introduced to a new pond for the first time, it needs to be put in a quarantine tank. 

This tank is a secluded space away from the rest of the pond where sick or injured koi fish can recover and not risk further harming themselves or spreading illnesses and parasites to other fish within the pond. 

Similarly, new koi fish must be quarantined in a separate enclosure to make sure they are healthy enough to survive being introduced to a new pond setting. 

This quarantine period also allows you to check them for illnesses and parasites and acts as a secondary line of defense against  introducing health problems to the rest of your pond. 

Quarantine tanks can make a massive difference in the stability and health of your koi fish enclosure and are vital to your koi care routine. 

For babies, also known as koi fry, keeping koi fish in a fish tank is a great idea. 

Koi fry cannot easily survive within a pond and often need assistance to keep them from being eaten by the adult koi fish and to ensure they are getting the nutrition they need in order to grow and develop into healthy little fish. 

Having a tank ready when you are hoping to spawn koi or breed them to create eggs is a great idea, as it means you are prepared for the arrival of the eggs and impending hatch date. 

Plus, it makes the process much easier and gives you a better viewing window into the health and development of your little koi fry. 

They cannot stay in the tank forever but for the time they can, it will be a massive asset to their overall care and health. 

koi fish in a fish tank

Koi Fish In A Fish Tank Can Serve A Short Term Purpose

So, in short, while koi fish cannot stay in a tank enclosure forever, they can benefit from being housed in one for a short period of time for quarantine purposes or when hatching and developing as koi fry. 

Tanks can serve a very vital purpose and keeping a koi fish in a fish tank is something that is necessary sometimes but is not viable as a long term housing method. 

Keeping this in mind will help you create a care plan and wellness backup plan that is strong and able to handle anything koi care throws at you.