Koi Betta Fish: Care Sheet and Informational Guide

Koi Betta: Marble variation of Betta splendens

Koi bettas are a specific variation of marble Betta splendens with striking patterns that resemble that of a typical koi fish. These are freshwater fish native to Southeast Asia. A marble betta fish is referred to by its physical blotched appearance, but what it really represents is the result of selective breeding that causes special genes called jumping genes or transposons. 

Basically, these jumping genes are pieces of DNA that can move from one part of the genome to another within a cell, which explains why these fish can change their color or increase the intensity of their pigmentation at any time. Because these fish have been selectively bred, you will not see a koi betta fish variant in the wild. 

Koi are the standard type of marble betta, but other types include Halfmoon, galaxy, and fancy. No matter how they look, they are still Betta splendens and must be cared for similarly to any other Betta.

Koi Betta and its varieties

A Koi Betta fish can be found in a wide variety of colors and fin varieties, and new varieties are usually variations of existing marble bettas in various colors and sizes.

Galaxy Koi Betta Fish

On Betta fish, the Galaxy Koi Betta is a label with specific colors and patterns. The base of male varieties is primarily blue or red(as shown in the image below). They’ll have less clear colors, though some iridescent scales will appear. There are more fins and tails on the Galaxy Koi Betta than there are on the Plakat variation.

Image of galaxy koi

Koi Plakat Betta

Unlike other Betta varieties, Plakat has shorter fins and tails. The colors and patterns of Koi Betta are more common in Plakat, which tends to have more Cellophane coloring.

Koi Nemo betta

Plakat Bettas, such as these are among the most popular and beautiful fish varieties available today. Bettas of this popular variety are colored with high-grade body and fin patterns. This fish displays a variable mix of most colors, often displaying up to five colors.

Koi Halfmoon Betta

The Koi Halfmoon Betta displays a fascinating array of coloration, along with long, sleek finnage(as shown in the image below). Koi Halfmoon Bettas are extremely high-grade longfin varieties. The specimens of this fish come in a wide range of colors and usually display five or more colors on one specimen as well just like the previously mentioned Koi Nemo betta fish.

Image of halfmoon betta male in aquarium

Yellow Koi Betta

Yellow Galaxy Koi Halfmoon Male Bettas are an outstanding coloration fish of the plakat fin and body type. These specimens come in a variety of colors, but these species are largely yellow in coloration.

Image of yellow koi betta

Other Koi betta fish types include Baby Koi betta, Orange koi betta, etc.

Image of orange koi betta

Koi Bettas: Origins and care

Betta splendens (Siamese fighting fish), commonly known as the betta, is a freshwater fish native to Southeast Asia. There are many countries in this category including Vietnam,  Indonesia, and Thailand, just to name a few. Normally, this region experiences warm weather, and water quality is excellent due to the regular rainfall.

As such, a koi betta should be kept in warm water with a constant temperature between 22 and 26 degrees Celsius. Temperatures between 22 and 26 degrees Celsius are ideal for them, and they are tolerant of temperature swings. However, these should be avoided as they weaken the immune system and leave them susceptible to opportunistic diseases like Ich and Fin Rot.

Furthermore, the water should also be of high quality. It is therefore essential to constantly monitor water conditions at least weekly for changes in pH, ammonia, and nitrite levels.

It’s also important to change the water twice a month to keep the aquarium clean. The koi betta prefers an aquarium with dense vegetation with plenty of hiding places. In addition to providing food, live plants also provide oxygen.

Ideally, the water in the tank should be soft with a pH range of 6.0 to 8.0; softer water is better. To mimic their natural habitats, water movement should also be limited. Also, they can survive low oxygen saturations in water because their respiratory organ allows them to breathe surface air. As a consequence, the water surface should be accessible for them. 

Check out this article to know how many GloFish in a 10 Gallon Tank

Koi betta tank requirements

Koi Bettas can live in small spaces, so tank size isn’t too important for them, but a minimum tank size of 2.5 gallons is recommended. More space is always appreciated, especially if you want some companions for your Betta. Besides being less expensive, smaller tanks are also more convenient, easier to maintain, and less complex.

The water chemistry and temperature of larger aquariums are, on the other hand, more stable, which makes them better for fish health. You can also build a lot more vegetation, ecosystem, fish, and so on.

Filters must be installed in the tanks to keep the water clean, preventing the accumulation of toxic materials that can impair their immune systems. A gentle filter is recommended for koi bettas, as they cannot swim in turbulent water.

Moreover, you should also buy a heater to keep the temperature constant, as they come from tropical Southeast Asian regions where the weather is always hot. This will require that you maintain the water’s temperature between 25-27 degrees. Too high a temperature speeds up the aging process, while too low a temperature increases the risk of infections.

A thermostat will certainly make the most ideal heater more convenient to monitor, even though it is not a requirement. In addition, installing a heater in a tank that is smaller than 5 gallons is inconvenient.

It is important that you provide plenty of plants and hiding spots like caves for Koi fish to survive. Since they live in streams with thick vegetation, make sure you provide plenty of plants and hiding spots. In addition to sleeping and resting on leaves, they like to rest on wide branches. As for koi betta fish tanks, gravel is suggested as the most ideal substrate.

Image of a Koi in an aquarium

Tank companions for Koi Betta

The Koi Betta fish is highly territorial, and he will need a lot of space, so it’s important to take this into account when selecting a tank. You should consider a tank that is spacious enough to comfortably accommodate the Koi betta and any companion fish. It is strongly recommended that you introduce the Koi betta into an established tank when mixing it with other fish. In doing so, the Koi betta will become less violent and won’t feel that his territory is being invaded, or attack the other fishes immediately.

Koi betta fish should be kept with peaceful tank mates who are dull-colored, short-finned, and have a tropical environment as well. It is imperative that they are not aggressive, and certainly not predators. Fin nippers, as well as other fish species with a similar appearance and, most importantly, other male betta fish, must be avoided.

A few good tank mates for Koi Bettas include Barbs, Livebearers, Female Bettas, Snails, Larger Shrimp, Corydoras, Plecostomus, and other Bottom dwellers. Additionally, aggressive cichlids, male Bettas, and dwarf shrimp are among the ones not suitable for Koi Bettas tank mates.

A healthy Koi Betta diet

A Koi betta fish feeds on insects, insect nymphs, and larvae in the wild. It is because of this that they have upturned mouths, ideal for catching insects rising from the water’s surface. Betta koi fish have carnivore-like digestive systems that allow them to digest meaty diets, and their upturned mouths enable them to capture insects that fall into the water.

Live insects and larvae should be fed to them in captivity to maintain proper health. They will, however, easily adapt to eating frozen and frozen dried foods. Koi betta fish can be fed frozen, and fast-dried brine shrimp, glass worms, and daphnia, which are all good choices for feeding your Koi betta fish. Baby brine shrimp or fine baby food should be fed to young Koi betta fries. 

Feeding Koi Bettas

Koi Bettas are extremely easy to feed. It is common to see Bettas looking for something to eat minutes after introducing them to your tank, as healthy Bettas of all kinds have a voracious appetite. Although prepared foods are very useful, it is best to increase their nutritional value with frozen and live foods as well.

Mature fish can be fed once or twice a day; splitting the meal up twice daily; while young fry should be fed up to three times a day.

If fed foods that expand in the stomach, such as dry foods, a betta’s stomach can stretch, which can be dangerous. The fish should be fed enough to round out the belly. Depending on the fish’s size, age, and even gender, this varies. Due to carrying eggs, mature females often have rounded bellies. So Fish that appear to have a rounded belly may not necessarily be bloated or constipated. You should take special care not to overfeed your fries since the leftover food in the tank can become toxic and cause death.

The lifespan and growth of a koi betta

Like other types of Betta fish, Koi Bettas also have a similar size. Compared to females, males can grow a bit longer, but gravid women have a larger circumference. The Koi Betta fish can reach a maximum length of three inches. In ideal conditions, if they are fed properly and kept in the proper water, they can live almost three years.

Koi Betta Fish Temperament

Betta splendens are well known for their aggressive nature. Selecting the type of fish or aquatic life that would cohabit with your Koi betta fish is a personal decision. With a variety of bottom-dwelling aquatic creatures surrounding them, the Koi betta will thrive. However, there is a possibility that some fish in the middle and topwater levels may be threatened by the Koi betta fish. It is common for male koi bettas to attack other males. In addition, they become aggressive towards females when the females approach the nest. Additionally, some tank mates may exhibit aggression towards them.

Male Koi Betta And Female Koi Betta Fish

As with many Siamese Fighting fish (Betta splendens), male and female koi bettas exhibit different colors. Female bettas display their color pattern on their fins, in contrast to the males who have more color and color patterns.

Generally, males have wider and bulkier ventral fins than females. Their bodies are bulky with curved heads, and their colors are brighter than their female counterparts. As opposed to males, females have slender bodies. Their stomachs are more rounded while spawning and their egg spots resemble lumpy white spots between the head and ventral fins.

Breeding Koi Bettas

You will have an easier time breeding your fancy-looking Koi Bettas if they are kept warm, well-fed, and in clean, filtered water. Koi betta fish are easily breedable in any 10-gallon tank. Choosing the right aged fish is very important. Therefore, it is recommended to choose fish that are under a year old as they are ideal to breed since they are still very fertile. When one is old, the urge to breed diminishes, so they should be conditioned and then bred.

The male koi betta usually builds nest-like structures to attract a female to come wandering by, in the hopes of enticing her under his love nest. For the best result, a steady diet of invertebrate-based foods is essential in addition to the proper water conditions. Make sure the pH of the water is about 7.0 and the temperature is 27°C or higher.

She will acknowledge the male’s fin displays and join him under his bubble nest once she has swelled with eggs. After embracing several times, they would curl up around each other. Immediately after being laid, the eggs are fertilized, and the male koi betta collects them and spits them into a bubble nest.

Betta males usually build a bubble nest where their eggs are kept. You should provide an area where the female can hide, as the male becomes aggressive while guarding the eggs. All the eggs will be watched over by the male as they develop.

Ideally, at this point, you should treat the tank with Pimafix, an effective yet gentle antifungal agent. It is extremely likely that you will experience fungal infections on eggs from your Betta fish, particularly if it is your first time spawning. Besides going bad, infertile eggs spread bacteria to healthy eggs. An experienced male koi betta will usually eat fungus-covered eggs, however, more inexperienced males may ignore them or end up eating them all.

As soon as the young hatch, they consume the yolk sack. We suggest that you remove the male betta after 2 days since it could feed on the younger fish.

 Are Betta Koi Fish Right For You?

Betta splendens Or Siamese Fighting Fish fans, in general, may find the Koi Betta an interesting addition to their collections. This fish exhibits color changes over its lifetime as a variation of the Marble Betta.

Koi Bettas are similar to other types of fighting fish for those new to fishkeeping. When you don’t have the space to house a big Koi carp(more specifically Nishikigoi, which are colored varieties of the Amur carp) when they grow up, you can enjoy the same color patterns in the Koi Betta fish, which does not require any outdoors space. At the end of the day, we are all driven by our own interests. 

Where Can I Buy Koi Betta Fish?

If you are fond of Betta splendens, specifically the Koi Betta, you will probably be interested in knowing where Koi Betta fish are for sale.

The Internet is a great place to begin your search for an online store. The Koi Betta is available from breeders, clubs, and online pet stores. A reputable online seller will provide fast shipping and guarantee live arrivals. Breeders and shops in your area usually have websites, and you benefit from proximity. Koi Betta might even be available at a local branch of larger chains. When you shop online overseas, there are a lot of risks, and even reputable dealers may not be able to get you your Betta fish. Furthermore, you will be charged more for shipment to ensure that the fish reaches you quickly.

Still, as shipping is more reliable, national sources are your next best option. Petco, for example, sells them across North America. Large stores’ stocks of Betta fish can be hit or miss for customers due to their varying quality. One of these is the tendency to have more colorful male stock since they are usually larger. The pet section at Walmart and other big-box retailers might sell Betta splendens, but there are so many different varieties that selection can be overwhelming.

For finding Koi Betta for sale, you need to shop at independent stores that specialize in aquariums. There are many different colors and types available, including Koi Betta fish. It is not uncommon for customers to find females as well as males, and you may even find a breeding pair.

Trader magazines are another source to search for pet Koi Betta. However, if you look online, you’ll likely find local, national, or worldwide sources for Koi Betta fish services more efficiently.


What is a koi Betta?

Koi bettas are a specific variation of marble Betta splendens with striking patterns that resemble that of a typical koi fish. These are freshwater fish native to Southeast Asia. They are usually a result of selective breeding which causes special genes called jumping genes or transposons.

Are koi Bettas aggressive?

Betta splendens are notorious for their aggression, and Koi bettas are no exception.

How expensive is a koi Betta?

The cost of the fish can vary from place to place, but generally, they can range between $14 and $25. Depending on the rarity of the fish, the price can go up.

Is a koi Betta a Plakat?

The Koi Plakat Betta possesses the ever-popular plakat fin and body varieties. It is a fish with a very rich coloration. There are specimens of this fish with a mix of colors, often displaying as many as five colors at a time.

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