Can Koi Fish Be Kept in an Aquarium?

-- By Carol

Koi fish are the perfect addition to an aquarium if you want to brighten it up. There are various benefits of owning koi fish (as covered later in this article).

If you’re thinking of keeping koi fish in your aquarium, this one is for you.

Here are some tips to keep koi fish in your fish tank and ways to take care of them.

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Can I Keep Koi Fish in My Fish Tank?

Koi fish can live in your aquarium and like all other types of fish, you need to take care of them or they might not survive for long.

Koi fishes are big, so you need a large aquarium so that they can swim freely. If they do not have enough space, they might not be able to live well.

Koi fish can live up to 50 years, so before getting them, you need to make sure that you are ready for a long-term commitment.

Koi fish may not always blend well with other fish since they are quite messy, but with the right care and maintenance, you can add them to a fish tank with other fish.

Also read: Why are Koi Fish so Popular?

Stuff You need to know about Koi fishes

Koi fish are peaceful and can form groups of 5 to 15 fish.

These groups then swim in coordination and look very aesthetically pleasing in a pond or an aquarium.

Unlike some fish that like to stay on one level, koi fish are fast and tend to go to every level of your aquarium.

Sometimes, you might see them near the surface and at other times, they might be at the bottom.

When it’s extremely cold, koi fish are most likely going to be swimming at the bottom.

Koi fish are extremely active and don’t get tired easily, so you can expect them to swim in your aquarium at various times of the day.

When looking for food, koi fish will dig into the sediment and have seeds, which might sometimes even disrupt your aquatic plants.

They eat like a vacuum since they inhale the food in big gulps, which helps them filter the dust and grime.

Koi fish can reach up to 3 feet, which is much larger than other aquarium fish.

They have barbells on both sides of their face, no teeth, which helps with gulping food, and a round snout.

The female koi fish is bigger than the male fish and has more circular bodies.

Koi fish are usually silver or white with bright markings and spots, so they stand out in a pond or an aquarium.

Also read: Are Koi Fish Good for Aquaponics?

Types of Koi Fish

There are different types of koi fish that you can add to your aquarium.

You can tell them apart by their markings and color.

Here are a few types of koi fish:

Butterfly Koi Fish

The butterfly koi fish are long and come in different colors.

Japanese Koi Fish

The Japanese koi fish are the most common type of koi fish, and they come with red and orange markings.

Dragon Koi Fish

The dragon koi fish have white and black markings that may change depending on the time of the year.

Black and White Koi Fish

The black and white koi fish are completely white and have black markings and spots.

They have different patterns, which may change with seasons.

How to Setup the Aquarium for Koi Fish?

Koi fish are known to be one of the most active aquatic species and can swim during the day and night.

Here are a few things to keep in mind before getting koi fish for your aquarium.

Set Optimal Temperature and pH

Koi fish can survive in tropical and cold temperatures, but the ideal water temperature for a koi fish is above 70 degrees Fahrenheit.

During the winter season, it is best to install a heater in your fish tank, or your koi fish might freeze.

Unlike some aquatic life, koi fish do not need water flow to float in the tank. Make sure to keep the pH of your fish tank between 7 to 9.

To keep the pH-controlled, you can always crush limestone and add it to your fish tank.

Use a Muddy Substrate

The substrate of your koi fish tank should be muddy.

Adding lots of plants in a koi tank might not be the best idea since they dig into the substrate to find food.

You can always add decorations and fake plants since they can always be put back into place.

Use Big Aquarium/Tanks

Compared to other pet fish, koi fish need big tanks.

A koi needs a minimum tank size of 250 gallons of water, so a group of koi fish might need 1000 gallons of water to survive.

The size of your aquarium should be at least 6 feet as koi fish like to swim around.

Make sure the aquarium has deep and shallow water because koi fish will visit every level of your aquarium, depending on the weather and time of the day.

Check New Additions for Disease/Infection

Koi fish can be easily infected with a fatal virus called Koi herpesvirus or KHV.

This virus is contagious and once a koi fish is infected, there is a huge chance that it will die in a couple of days.

The fish that survive might carry the infection, which can further infect the other fish and ultimately, the whole tank.

A koi fish has KHV when they cannot breathe properly or have white and red spots on their gills.

It is always a good idea to remove the infected fish from the tank and place them somewhere else before they infect more fish.

If you think it is too late for that, simply euthanize the whole tank.

You can prevent KHV from spreading in your tank by carefully examining your fish before adding them to the tank.

Check their gills, see if they can breathe properly, and keep them in a separate place for at least 2 weeks before letting them mix with other fish in the aquarium.

Besides KHV, koi fish can also be infected by ulcer-related diseases and fish lice, which can also affect other fish in the tank.

Unlike some fish who need optimal water quality at all times, koi fish can survive in water that is not clean.

However, it is a good idea to clean your tank and remove the water every few weeks so your fish do not get sick.

Make sure to remove and clean the filter every 3 to 5 weeks.

Also read: Do Koi Fish Need a Filter in Pond/Tank?

Feed Your Koi Fish Well

Koi fish tend to consume a lot of food and are known to eat similar food as goldfish. They can eat algae, insects, and seeds.

Koi fish do not eat other fish, but they might eat their eggs. In a well-maintained fish tank, koi fish may eat plant material, algae, and seeds.

To keep koi fish away from your aquatic and decorative plants, it is a good idea to add weed and algae in your tank so they can eat those instead.

It is best to feed your koi fish 3 times a day because they will continue to eat whatever is available in the tank anyway.

What Other Fishes Can live with Koi Fish in Aquarium?

The good thing about koi fish is that they are extremely peaceful and tend to stick to their type.

They will also not harass smaller fish or try to eat them.

However, they consume a lot of food, which might not be the ideal aquarium situation for other marine life.

You can add Goldfish to your koi tank. When koi and goldfish swim together, all you can see are different colors, which gives an interesting vibe to your aquarium.

If you’re a fan of bright colors, this combination is a good choice for you. Goldfish and koi also have similar diets, so it will be easy for you to feed both at the same time.

Sunfish can also easily blend with koi fish. You can also add Catfish, Killifish, and Minnows with your koi fish.

Before adding all these fish, keep in mind that you will need a large tank.

Koi fish don’t get along well with bluegill. Both these fish compete for food, which might harm other fish in your tank.

We would also recommend not adding Small Crypinids in your koi tank as Crypinids get nervous around big fish.

In short, you can add koi fish to your aquariums. Not only do these fish add color to your home, but they are also easy to take care of as compared to other large fish.

One of the best things about koi fish is that there are various types to choose from.

Koi fish also tend to live a very long life, so if you think you have what it takes to take care of them for decades, you can add them to your tank!

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