Koi Betta Fish: Discover Our Complete Care Guide

Part of the fun of owning a betta fish is watching its colors dance across your tank. If you opt for a koi betta fish, the spectacle will be even better. These fish have a vibrant marbled coloration that’s prized by aquarists.

Read this care guide to learn how to keep your koi betta fish happy and healthy. 

Koi Betta Fish Overview

Despite their dual name, koi betta fish are regular bettas with no koi genetics. What makes them special is their gorgeous marbling, reminiscent of the colors on a koi carp.

Koi betta fish were bred from marble bettas for an even more distinct look. The marbling comes from a gene called a transposon that destabilizes pigmentation and can change over time. 

To maintain the genetic profile, breeders selectively breed koi betta fish. Almost any color pattern is possible, but rich red, orange, black, and yellow tones are what you’ll see most. These colorful patches appear with shimmering, iridescent scales. More expensive koi betta fish might have splashes of blue, green, pink, or purple.

Koi Betta Fish Behavior & Temperament

Koi betta fish tend to be aggressive and unfriendly, especially the males. Males and females usually only live together if they’re breeding. Otherwise, the male koi betta fish will relentlessly harass your female bettas, chasing them to breed and attack. 

Many owners keep their male bettas in solo tanks to minimize stress. Tank mates are possible, but they should be calm fish that look nothing like male bettas. Animals like snails and frogs are okay, too. 

Female Koi bettas have gentler natures. They’re a better choice if a busy tank full of life is a priority. It may even be possible to keep multiple bettas in “sorority.”

Koi Betta Fish Care

The average koi betta lives for two to three years. However, with luck, good genetics, and the right tank, your betta may live for five years or even longer. Getting their care just right is essential. 

Here’s what you should know.

Tank

Koi bettas need plenty of room. For them to thrive, their tank should be at least five gallons. You may also need a water heater as they live best in water that’s 75–82 degrees Fahrenheit.

A filter can help you keep the water clean, but make sure it’s not too strong. Koi bettas may struggle to swim in tanks with a fast-flowing current. That’s because bettas in the wild live in shallow, stagnant ponds.

Feel free to decorate the tank with toys and plants. Live tropical plants like Java ferns do well in the betta’s warm tank. Whatever you decide to add, avoid sharp edges that might tear their fins.

Food

You must provide high-quality, high-protein food to care for your koi betta. They’re hunters who gobble anything they can catch and fit in their mouths.

Fortunately, their tiny size limits their appetite, so feeding them can be quite affordable.  Every pet store carries betta pellets or flakes. If you want to treat these carnivores, stay away from the fruits and veggies that a goldfish might enjoy and turn toward bloodworms and baby brine shrimp. 

Betta should eat twice a day for less than two minutes each time. 

Diseases

Like many aquarium fish, bettas are prone to Ich. This disease develops when the tank’s water conditions are not quite right, and the fish gets stressed. The main symptom is white dots appearing on the scales. 

Fin rot is another common problem. It can happen when bacteria eat at your betta’s lovely fins and destroy them. Keeping the tank adequately heated is the best way to avoid fin rot.

Breeding 

Many koi betta fish owners love the experience so much they decide to breed koi bettas. It can be a gratifying process that preserves the famed marbling for future aquarists. 

However, it can be time-consuming and complicated. You’ll also have to invest in multiple tanks, as your female and male koi bettas can’t live together permanently. You’ll need a tank for each sex and one for breeding. 

Once moved to the breeding tank, it’ll likely take a few weeks for the bettas to spawn. The female will lay her eggs in a bubble nest built by the male. At this point, you should remove your female koi betta for her safety. The male will care for the eggs. 

However, his loving behavior stops once the new bettas are hatched, and he might eat them if he’s not removed soon after their birth. 

Where to Find a Koi Betta Fish 

Koi bettas may be more difficult to find than an average goldfish. They’re sold online and at large or high-end fish stores. Expect to pay around $20 to $50.

The photo featured at the top of this post is © Matt Albanus/Shutterstock.com