Koi Betta Fish: Care, Breeding, Lifespan, Eggs & More

Koi betta fish is a fascinating and captivating species that have become increasingly popular in the aquarium hobby. These fish are known for their unique and striking marbled coloring resembling koi fish patterns. Koi bettas are relatively easy to care for and make great pets for both beginner and experienced fish keepers.

In this article, we will explore the world of koi betta fish, covering topics such as their care, breeding, lifespan, and eggs. We will provide valuable information on creating a suitable habitat for these fish and ensuring their well-being.

With the proper knowledge and care, you can enjoy the beauty and charm of these magnificent fish in your own home. Join us on this journey of discovery and learn everything you need to know about koi betta fish.

Key Takeaways

  • Koi betta fish are hardy and easy to care for, with a minimum tank size of five gallons and preferred water parameters of a pH level of 5.5 to 8.0, a water hardness of 4 to 8 dGH, and a temperature of 75 to 84 degrees Fahrenheit.
  • They prefer a protein-rich diet and can be fed commercial pellets, bloodworms, brine shrimp, and more.
  • Koi bettas should not be housed with aggressive tank mates but can cohabitate with non-territorial passive fish like Ember Tetras and Kuhli Loaches.
  • Breeding koi bettas requires a separate breeding tank, timing, and antifungal treatments to prevent egg issues.

Species Summary


Koi bettas are a variation of Betta splendens. While these fish may not be found in the wild, they are descendants of wild variants that live in shallow bodies of water like rice paddies, stagnant pools, and slow-moving streams. This section will provide an overview of koi betta fish’s average size, lifespan, and appearance.

Average Koi Betta Fish Size

Koi betta fish can grow up to 3 inches in length, with koi plakat bettas tending to be on the shorter end at 2-3 inches long.


Potential owners should carefully consider the longevity of these unique and vibrant fish, as koi bettas have an average lifespan of three to five years with proper care. Aging in captivity can be affected by various factors, including water quality, diet, and stress levels.  Providing them with optimal living conditions is crucial to ensure that koi bettas live their full lifespan.


With their unique marbling patterns and expansive fins that flow like silk drapery, koi bettas are a stunning addition to any aquarium. The marbling gene in koi bettas creates a spectrum of color in the fish, resulting in a wide range of color variations that mimic the multicolored nature of koi fish.

Koi bettas have sharp-edged patches of color that usually have a sudden color change, adding to their striking appearance. Jumping genes, also known as transposons, are responsible for the color-changing abilities of some fish throughout their lives. While this can make it challenging for breeders to determine their success, it also adds to the unique and special nature of owning koi betta fish. The unknown aspects of their appearance only add to their allure.

Koi bettas are not a different species but have been selectively bred for their unique marbling patterns. The most common type of koi betta is the galaxy koi betta with iridescent scales of deep blue and turquoise, creating a galaxy-like effect that captivates any observer.

Their iridescent scales and sharp-edged patches make them stand out from other betta fish, and their stunning appearance is highly sought after in the pet trade. With their eye-catching colors and patterns, koi bettas are sure to be a centerpiece in any aquarium, adding beauty and elegance to any aquatic environment.

Koi Betta Fish Care

Maintaining the right water parameters, including temperature, pH levels, and water hardness, is crucial for their health.

Setting up their tank with proper filtration, heating, and natural decor is essential, and regular monitoring for potential diseases is necessary to keep these beautiful fish healthy.

Tank Size

Suitable tank size is a crucial factor in properly caring for koi betta fish, as they require a minimum of five gallons of space to thrive, and a larger tank is always better for these fish. A larger tank allows for more swimming space, which is essential for koi bettas to display their expansive fins and vibrant colors.

Water Parameters

The water quality in the tank is crucial for their health and well-being. In order to create a suitable environment for koi betta fish, it’s important to balance pH, water hardness, and temperature. Here are three essential factors to keep in mind when it comes to water parameters for koi betta fish:

  1. Testing water quality: It’s important to regularly test the water quality in the tank to ensure that the pH level, water hardness, and temperature are within the appropriate range for koi bettas.
  2. Balancing pH, water hardness & temperature: Koi betta fish prefer a pH level of 5.5 to 8.0, a water hardness of 4 to 8 dGH, and a temperature of 75 to 84 degrees Fahrenheit.
  3. Importance of filtration and water change frequency: Koi betta fish require a good filtration system to keep the tank water clean and healthy, and regular water changes should be performed to maintain water quality.

Setting Up Their Tank

Creating an ideal environment for koi betta fish requires careful consideration when setting up their aquarium.

Decorating tips for koi betta tanks include adding natural decors such as plants like Anubis, java fern, Cabomba, and water sprite. Good lighting will bring out the koi betta’s beautiful coloration. Rock caves and smooth plastic decorations add a lot to the underwater habitat and give your fish plenty of objects to explore.

However, it is important to avoid overcrowding the tank with too much decor, as this can lead to poor water circulation and an unhealthy environment for the fish. When it comes to choosing a substrate material for your tank, sand or gravel are great options to consider. While these fish don’t have a specific preference, choosing something that can help keep your plants healthy is always a good idea.

Investing in a top-notch filtration system is crucial for your tank’s well-being. Make sure to choose one that can efficiently cycle the tank water. Keep in mind, though, that the system’s outlet should not create a strong current. To prevent this, use sponges to reduce water flow and maintain a relatively still environment in the tank if necessary.

Potential Diseases

Now that you’ve set up your koi betta’s tank, it’s important to be aware of common diseases that can affect these fish. Prevention measures should be taken to ensure that your koi betta remains healthy.

Some common diseases that can affect koi bettas include Ich and fin rot, and these diseases can be caused by environmental factors such as poor water quality and stress. It’s essential to maintain a clean and healthy tank environment to prevent these diseases. This includes regular water changes, proper filtration, and avoiding overfeeding.

Food & Diet

Nutritional requirements for koi bettas are similar to other betta fish, and a varied diet is essential to keep them healthy. Commercial pellets are a good option for their primary diet, but supplementing with live or frozen food can provide additional nutrients.

Bloodworms, mosquito larvae, brine shrimp, and daphnia are all excellent options for dietary supplements. Overfeeding can lead to health problems, so it is essential to stick to a feeding schedule and avoid giving them too much food.

Behavior & Temperament

Understanding the behavior and temperament of koi betta fish is crucial for providing them with an appropriate environment and maintaining their well-being in captivity. These fish are known for their aggressive behavior, particularly male bettas. Therefore, aggression management is necessary when keeping koi bettas in a community tank.

The best way to avoid aggression is to keep a single male betta or a group of females with non-territorial, passive fish as tank mates. If you want to avoid aggression altogether, these fish are perfectly content to stay solo. They don’t need others to keep them happy and healthy.

Social behavior can be enhanced by providing environmental enrichment, such as hiding places, plants, and decorations that mimic their natural habitat.

Tank Mates

Cohabitating koi bettas with peaceful, non-territorial passive fish like Ember Tetras and Kuhli Loaches can create a beautiful and harmonious aquatic environment that will be a joy to observe.

Koi bettas are known for their aggressive tendencies and should not be housed with other male bettas, but they can coexist with a small group of females or non-territorial passive fish.

The best tank mates for koi bettas are those that are peaceful and have short fins, such as Ember Tetras, Kuhli Loaches, Harlequin Rasbora, and Cory Catfish.



Breeding koi bettas requires careful planning, proper tank setup, and patience to achieve successful results. Koi bettas should be at least four months old or around one year. The breeding tank should be shallow, three to five inches deep, and heated to a temperature between 76°F-84°F.

The female koi betta should be introduced to the breeding tank at least an hour before the male to allow her time to adjust to the new environment. The mating process usually lasts for four to six hours, during which the male will build a bubble nest, and the female will lay her eggs. Afterward, the female should be removed from the breeding tank to prevent her from eating the eggs.

As little ones grow, make sure to give them a  diet of infusoria, baby brine shrimp, and other yummy high-protein foods. Breeding koi bettas can be challenging, and monitoring the eggs’ development is essential. The fungus can develop on the eggs, and antifungal treatments are available to minimize issues.

Frequently Asked Questions

How long does it take for koi betta eggs to hatch?

The incubation period for koi betta eggs is usually 24-48 hours, with a hatching success rate that depends on egg care and the breeding process.

Can koi betta fish survive in a tank without a filter?

A filterless tank may compromise water quality, reducing the survival rate of koi betta fish. In their natural habitat, oxygen levels are higher, making filtration necessary for indoor tanks to maintain a healthy environment.

How often should water changes be performed in a tank with koi betta fish?

Regular water changes should be performed every week to maintain a healthy tank environment for koi betta fish.


In conclusion, koi betta fish is a beautiful and fascinating variation of Betta splendens that require proper care and attention to thrive in captivity. Their hardy nature and adaptability make them an excellent choice for beginner fish keepers, but it is essential to ensure their tank setup is suitable with proper filtration and water conditions. Providing a varied and balanced diet is also crucial for their well-being.

When considering tank mates, choosing peaceful species is important. Breeding can also be a rewarding experience for experienced fish keepers but requires careful planning and attention to detail.

With proper care, koi betta fish can live for several years and bring joy and beauty to any aquarium. Overall, these unique and stunning fish make a wonderful addition to any fishkeeper’s collection.