Koi Betta: Ultimate Guide (Care, Diet, Breeding & More)

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Written By Matt Stevens

Hi, I'm Matt! I've been obsessed with fishkeeping for over 15 years now and created this site to share my knowledge with others.

Koi Betta is a colorful freshwater fish that stands out in any aquarium.

If you’ve seen them online or at local pet stores, you could be wondering if caring for them would require the same commitment as most Betta fish.

Are they similar to the conventional Koi fish? Who are Koi Bettas’ best tank mates? And would they thrive with my favorite aquarium snails in captivity? You will probably ask. Well, Koi Bettas are no different from most freshwater Bettas.

However, caring for them can only be fun if you first understand what makes them stand out in captivity. Thankfully, we have created a comprehensive guide to address everything about Koi Betta care.

In the forthcoming paragraphs, we discuss handy tips to help you understand if Koi Betta could be the missing piece of the puzzle when creating a dream aquarium. Specifically, we will discuss the fish’s origin, lifespan, tank size, diet, behavior, tank mates, breeding, and more.

Species Overview

So, what is a Koi Betta? 

Well, the intriguing story of Koi Bettas has Orville Gulley, a renowned hobbyist, at the center of everything. He successfully bred the very first variant of Marble Betta. And even though the whole story appears to go under the radar, he’s usually credited with discovering the beautiful Koi Bettas.

They were originally called the marbled fish, a name they have happily held up to date. They are best known for their impressive color intensities and charismatic behavior beyond peaceful coexistence with fellow tank mates. 

Also, they form admirable bonds with their owners, which can be interesting to watch during feeding.

Traditionally, Koi Bettas have been likened to the famous Japanese Koi carp. However, it’s important to note that the two species are not related in any way, not even by place of origin.

Naturally, they first originated from South East Asia before spreading to other regions around the world. What’s more, they are a distinctive variation of the conventional Marble Betta fish, with the name denoting their ability to change their color patterns as they age.

So, the next time you see a Koi Betta, be sure it’s not a hybrid fish involving the Betta fish and the Koi Carp varieties. Neither is it a conventional Koi fish.

Color Red, orange, white, and black
LifespanUp to 3 years
Care LevelModerate 
Behavior & TemperamentAggressive 
Compatibility Kept singly or with peaceful shoaling species
Food and DietCarnivores 
SizeUp to 3 inches
Tank SetupFreshwater with plants and caves
Tank Size (Minimum)10 gallons 


The flamboyant Koi Bettas are famous for their impressive lifespan in the wild and captivity.  

On average, a typical Koi variety will outlast most freshwater fish, living for up to 3 years with the best conditions.

If you deprive them of a few basic conditions, you can still expect them to at least pass the standard 2-year mark, thanks in part to their resilience. But if you restrict them to a substandard environment, it will be hard to guarantee their long-term safety, health, and well-being.


Koi Bettas boast the loveliest color patterns in the entire Betta family, and this will be evident from the very first time you see them at your favorite pet store.

At first glance, you will see a lovely freshwater fish with a striking color pattern that puts it ahead of the rest. 

Koi Betta’s appearance is not an exaggeration because a proper sighting of the male fish alone will instantly confirm that you are dealing with a genuinely amazing Betta variety.

On a regular mating routine, the male must win over the female species and that’s why they take on a more attractive display to complement their imposing presence in captivity. 

The jumping gene in Koi Bettas greatly influences their appearance, partially supporting many aquarists’ claim that these Bettas have more intense colors than the original Marble Betta fish.

Generally speaking, Koi Bettas have beautifully colored, free-flowing fins that assume sparkling black, blue, orange, yellow, white, or red hue. Apart from the small body sizes and shorter fins in the female fish, you won’t see much difference between the two genders.

Types of Koi Betta

As the fancy Betta variety, Koi Bettas exist in exciting color variations that can easily stand out in any environment.

We highly rate them among the most beautiful freshwater Bettas, and the eye-catching new varieties seem to have just taken their ranking to a whole new level.

In general, you will find up to 6 varieties of the traditional Koi Bettas from the local pet stores, including the following;

  • Galaxy
  • Fancy
  • Nemo Plakat
  • Samurai
  • Tiger
  • Candy

Let’s focus on the first 3 types of Koi Betta fish;

Galaxy Koi Betta

Galaxy Koi Betta is one of the most popular varieties many aquarists have attempted to keep at home. They take on sparkling scales with longer fins and tails that add to their exquisite appearance in captivity.


On the other hand, Fancy Koi Bettas have up to 3 beautiful colors. They are not as popular as the Galaxy types, but anybody who knows the Betta fish knows just how mesmerizing they can be as part of a community tank.

Nemo Plakat

Finally, Nemo Plakats are easily identified by the orange-red and black coloration. They are one of the most beautiful Koi Betta varieties you will ever find.


So, how big do Koi Bettas get? Like many Bettas, the Koi Bettas are small fish, only growing up to 3 inches long in total length. It’s not easy to keep them past the 3-inch mark, but with quality care, you might be lucky enough to have them for a few more years in captivity.

Koi Betta Care

Koi Betta care can only get interesting if you understand what your fish appreciate most in captivity, and by this, we don’t mean ideal tank mates alone.

Naturally, a proper tank setup is mandatory to keep healthy Koi Bettas at home. But even then, they will appreciate suitable additions in the form of tank decorations, an ideal filtration system, and proper aeration.

Let’s review the full guidelines in the next section;

Tank Size

Usually, Koi Bettas are kept and sold in small containers in local pet stores. Unfortunately, this tends to send the wrong message that these fish can thrive in small bowls and jars in captivity.

We agree the Koi Bettas need a modest environment to flourish in captivity but restricting them to tanks as small as ordinary jars is simply unacceptable.

At worst, be sure to set up a 10-gallon tank for every Koi Betta fish at home. But if you can find a larger tank, the better. Remember, at the end of the day, only a spacious room will save your fish from the wrath of devastating freshwater diseases like Ich.

Water Parameters

In terms of water parameters, it’s important to stick with the exact conditions in the fish’s original habitat.

There’s no shortcut to it, and sometimes, this means setting up a new tank specifically for Koi Bettas. Being the tropical fish from the Asian continent, these fish appreciate warmer conditions with every other parameter maintained within the suitable range as highlighted below;

  • Water Temperature: 70°F-85°F
  • Water Hardness: 5-35 dGH
  • pH Levels: 6.8-7.5

Koi Bettas need suitable pH levels to flourish in captivity, which is why you must test the tank water status frequently and make the necessary adjustments in time.

This is the perfect time to invest in a powerful aquarium testing kit to help you assess the water status more often. As part of the general care guidelines, don’t forget to cycle and change up to half of the total tank water every other week to give your Koi Bettas the best achievable environment.

What to Put in Their Tanks?

For the rest of the tank, there’s nothing more important to your Koi Bettas than the ideal decorations. Normally, this begins with adding a suitable substrate that mimics the natural riverbeds without exposing your fish to bodily injuries.

Koi Bettas are easy to care for, but their major drawback is that they eat anything that can fit their tiny mouths. So, when introducing the substrate, be sure it’s finely sized to suit its role as a decorative element and not another ordinary snack.

Soft sand is the best option, with gravel as the perfect alternative to replicate the wild environment.

What’s more, Koi Bettas enjoy their own space inside the tank, and you can even confuse them to be playing hide and seek with other tank mates. Accordingly, they need plenty of hiding spots created with a mixture of plants, caves, driftwood, and rocks.

Plants have the added advantage of maintaining water clarity and sometimes even acting as your Koi’s occasional snack. 

When it comes to general lighting, there’s no better way to approach it than avoiding strong heat sources. A powerful LED light is a nice-to-have inside the tank, but not mandatory.

Similarly, robust filtration is not mandatory if you keep Koi Bettas at home. The best strategy is to keep the tank water clean at all times and invest in simple sponge filters if you have to provide additional filtration.

Common Diseases

Koi Bettas enjoy a long, undisturbed life with quality care. That means you must pay attention to particular diseases commonly witnessed in the aquarium community.

Some of the most common conditions in the Koi Betta community include the hole in the head disease, swim bladder, pop eye, and Ich.

We always advocate for pristine tank water conditions if you keep any freshwater fish at home. But sometimes, the disease symptoms simply won’t go away even with the proper medications. And that should prompt you to measure and adjust the tank water besides seeking expert advice.

To prevent the common heath issues altogether, always stick to an ideal feeding routine and ensure your Koi Bettas live in the best possible environment.

Leftover fish food, new food, and new tank mates can quickly introduce new diseases to the aquarium. And it’s only by remaining watchful at all times that you can detect any significant shifts to the water parameters before it’s too late.

What Do Koi Bettas Eat?

Koi Bettas are a predatory species whose diet is dominantly made of meaty foods. They are fine with ordinary pellets but will appreciate a diverse mixture of high-quality live foods and occasional snacks.

In summary, Koi Betta’s favorite foods include small fish, brine shrimp, daphnia, bloodworms, earthworms, and mosquito larvae.

Don’t limit your fish to a specific food because most Betta fish are slightly selective when feeding. Most importantly, try to understand their favorite meal and plan your feeding routine accordingly. 

Behavior & Temperament

Koi Bettas resemble the conventional Betta fish with their temperament. They are naturally aggressive, with the male species showing a highly territorial behavior than the females.

It’s not entirely impossible to include them in a community tank. But to do so, you must set up a sizeable aquarium that takes every fish’s behavior into account.

A crucial aspect of Koi Betta fish care involves their territorial nature. The earlier you allow them to mark their territory, the better the chances of living peacefully with other fish.

You can achieve a lot by simply adopting simple strategies like creating multiple hiding spots inside the tank. That way, it’s easier to limit Koi Bettas’ aggressive tendencies and at least guarantee their long-term safety.

Regarding their activity levels, Koi Bettas are agile species and happy to coexist with other active fish as long as everybody enjoys well-defined territories.

Koi Betta Tank Mates

Your best bet for keeping Koi Bettas is to settle for similar species. You will find healthy fish with exciting color variations to help you create a dream aquarium even from scratch. But if you want to include new species in the same tank, small, active, shoaling species give you the best chance.

We’ve never seen multiple male Koi Bettas live peacefully in the same aquarium, and probably that’s one of the first things you will want to avoid when choosing new buddies.

Generally, Koi Bettas are best kept as the only fish inside the aquarium. And if you can’t find suitable tank mates, at least don’t go with the ordinary fin nipping fish or any species with flowing fins.

If you want to pair your Koi Bettas with other active swimmers, here are a few great options to consider;

When choosing new tank mates, the bottom line is to find similar-sized fish that can tolerate the same water parameters.


Koi Betta breeding is more challenging than it appears. And many aquarists who have tried it in the past have reported nothing but a huge disappointment.

Before everything begins, be sure to perform a proper cleaning routine to give your fish the best possible spawning conditions. The adult fish need proper conditioning with nutritious proteins for the first couple of weeks preceding the breeding season.

On the same note, try as much as possible to adjust the water parameters to suit the standard spawning requirements. During this period, slight adjustments to the water temperature to around 80°F would be necessary.

To jumpstart the breeding process, the male Koi Bettas will create bubble nests and spread their clusters on the water surface. Next, the females will release their eggs to be fertilized by the males.

Hatching takes just a few days if all conditions are satisfactory, with the young fish ready to survive off the eggs sacs for the first few days of their lives. It won’t be long before they are independent enough to fend for themselves.

Final Thoughts

Despite Koi Bettas’ notable aggression in captivity, they are easy to care for if you understand their needs. They are commonly confused with the conventional Koi fish, which adds to the endless misinformation regarding their care.

But if you’ve read our guide to the end, you might have realized Koi Betta care is just as exciting as you would have wanted it to be. Besides, these fish have no compatibility issues if the tank setup is fitting.

Now’s the time. Get your favorite pet fish, relax and enjoy as the beautiful Koi Bettas take over your aquarium.