Koi Betta Fish 101 (Care, Tank Size, Food & Tank Mates)

Koi Betta fish

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When it comes to keeping fish in home aquariums, few species prove more stunning than the koi betta fish. 

They are available in several colors, don’t need much care, and can even perform tricks. All you need to do is provide the right conditions, and they will live happy lives. 

So, what are the things that you need to keep in mind while taking care of koi betta fish? Let’s find out. 

What Is A Koi Betta? 

Koi bettas are a type of marble betta fish that have a cellophane-scaled body. Although they come in a variety of shades and striking patterns, the two primary colors are black and red. 

These color changes occur when the marble DNA alters its position within the genome. 

Are Koi Bettas Aggressive? 

The koi betta fish tend to be aggressive and may react violently towards other tank mates. In fact, the males are territorial, especially during the breeding season, and don’t like intruders venturing close to the bubble nest. 

Meanwhile, the females are comparatively docile but do display aggressive behavior. 

Koi Betta Fish Facts? 

These fish are available in different color combinations and don’t require much care in home aquariums. But in the wild, they live in rice paddies, slow-moving streams, and ditches. And to survive in these conditions, they have developed a special organ. Along with their gills, this organ allows them to breathe oxygen above the water surface. 

Types Of Koi Betta (By Colors)

Galaxy Koi Betta 

The Galaxy koi betta has iridescent scales to complement its red body but you will also find streaks of another color.  

Candy Koi Betta 

Just like candies are available in multiple colors, this koi betta variety comes in black, blue, red, and yellow. 

Fancy Koi Betta 

As the name suggests, these fish have a wide range of colors, at times more than three, although red is quite common.

Nemo Koi Betta 

Another betta fish with gorgeous colors is the Nemo koi betta, which has orange, red, and black hues across its body. 

Red Koi Betta 

Red is a common color among betta fish, but they appear highly attractive due to the different patterns and combinations formed with other shades. 

Blue Koi Betta 

They have a vibrant and deep-blue shade due to the shape of their pigments. In some cases, you may also find a tinge of green. 

Yellow Koi Betta 

You’ll find different shades of yellow; however, the yellow koi betta has lemon-colored fins and body. Additionally, they may have a black border along the scales. 

Orange Koi Betta 

Orange koi betta usually has a tangerine shade, but the color varies from pale to bright orange. Moreover, the tail appears reddish. 

White Koi Betta 

White koi bettas are extremely glamorous, thanks to their white fins and scales that are often opaque. Also, the body isn’t pinkish, which makes other features more prominent. 

Black Koi Betta 

The black koi betta has several sub-varieties, but the main highlight is its dark body and cellophane-colored fins. 

Koi Samurai Betta 

The koi samurai betta is quite popular because of its dragon scaling and bright red colors, interspersed with patches of white. 

Purple Koi Betta 

This variety has violet and pale-lavender shades, but occasionally you may find hints of red or blue, making them quite rare. 

Koi Betta Tail Types 

Veiltail Koi Betta 

Veiltail koi bettas have a long dropping tail that behaves like seaweed and trails behind the body to deliver an attractive appearance. 

Superdelta Koi Betta 

These fish have wider tails that extend up to 180 degrees and display striking patterns. Plus, each portion of the tail is triangular and has straight edges, like the Greek letter delta. 

Halfmoon Koi Betta 

Similar to the delta variety, the Halfmoon koi betta has a 180-degree tail, perfect for displaying numerous colors and patterns. 

Crowntail Koi Betta 

The crowntail variant is extremely eye-catching and features webbing that extends mid-way up each fin. This gives the tail a spiky appearance, like an upside-down crown. 

Plakat Koi Betta 

Unlike domestic bettas, Plakats have a shorter tail which is less fancy but in no measure less beautiful due to their color combinations. 

How Long Do Koi Betta Fish Live? 

In the wild, koi betta fish live for 3-5 years but their lifespan increases in captivity. Some fish can live for 8-9 years at home if they get the right conditions, thereby making them perfect as pets. 

How Big Do Koi Betta Fish Get? 

Both male and female koi betta fish reach a maximum length of three inches, meaning you don’t need to have a large tank to accommodate their fins. 

How Expensive Is A Koi Betta? 

The price of a koi betta fish depends on the type, with costs varying from $2 to $30. For instance, a regular female koi betta fish is available for $12-$15, while Paradise or Bumblebee bettas often cost $20. 

Of all the types, Elephant Ear bettas are the costliest, while Veiltail bettas are the least expensive. 

Gender: Koi Betta Male Vs. Female

Although both genders are of the same size, female koi bettas have a white spot called the ovipositor in front of the anal fin. Other than that, some males have a longer fin which helps distinguish them from females. 

Koi Betta Fish Care

How Big Of A Tank Does A Koi Betta Need? 

The smallest tank that you can purchase for a koi betta is 5 gallons. However, it comes down to the number of fish you want to keep. 

Most people keep 4-5 females, for which you’ll need a 20-gallon tank. That said, most koi bettas can live healthy lives in a 5-gallon tank without much difficulty. 

Do Koi Betta Fish Need A Filter? 

It would be best to install a filter even though koi bettas can survive in stagnant water. Not to mention, using a filter keeps the water clean, the fish stress-free, and helps mimic the natural conditions of their habitat. 

Do Koi Betta Fish Need A Heater? 

Another good practice would be to buy a heater for the fish tank to maintain the ideal water temperature. You must note that koi betta fish can’t survive in chilly conditions, and if the water temperature fluctuates constantly, it may shorten their lifespan. 

Do Koi Betta Fish Need Lighting? 

Betta fish are like humans and they need lighting to determine when to wake up and go to sleep. They like mild lights during the day, which you can switch on/off to help them wake up during the day or rest at night. 

Koi Betta Tank Care


The average water temperature for koi betta fish ranges from 72 to 86 degrees Fahrenheit. We must mention that they are quite sensitive to temperature fluctuations, so you should ensure that the water conditions aren’t too hot or cold for the fish. 

PH Level

Ideally, the pH range for koi betta fish should be within 6.0-8.0, but we’ve seen that they can survive in slightly acidic conditions. Now, for them to survive it’s essential that the pH is consistent, so make sure that it doesn’t fluctuate too much from 7.0. 

Water Hardness 

Apart from temperature and pH, it’s critical to ensure that the general hardness of water is between 70 and 330 ppm. Most koi betta fish prefer living in soft water, but they can survive in varying conditions, provided that the water isn’t very hard. 

Additionally, water hardness impacts the pH value, meaning you need to be vigilant.  

What Do Koi Betta Fish Eat? 

Koi betta fish primarily feed on insects and larvae in the wild as they need to consume a lot of protein. Also, being carnivores, they will eat most meat items. 

How To Breed Koi Betta? 

You’ll need a large tank, aquarium plants, heaters, and filters to breed koi betta fish. Once everything is in place, introduce a male and female pair to see how they respond to each other.

If the male turns aggressive, introduce a new female and stay patient; hopefully, you’ll find a pair that mates. 

Final Thoughts 

Are you confident that you have all the information needed for taking care of koi betta fish? 

Looking after these tiny fish isn’t a hassle; in fact, even kids can do it. That said, it’s important you keep them on a meat-based diet, ensuring that they receive the necessary proteins. 

Additionally, if possible, don’t introduce new fish into the tank. It would be best to keep the koi betta fish together but have a separate container to house the male and female during mating. 

On that note, we’ll leave you to iron out the details; hopefully, you’ll find colorful inhabitants to brighten up the home aquarium. Take care, bye! 

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Jeff Colt

Jeff Colt

Hello, I'm Jeff- an aquarium enthusiast with over 25 years of experience caring for a wide array of tropical fish, including koi, goldfish bettas, cichlids and more! For me: Aquariums are like jello - there's always room for more!

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