Koi Betta Fish

Koi Betta Fish : A Complete Guide


Ever wondered about owning Koi Betta?   Koi Betta is the common name of this Fish. Originally, it is called Siamese Fighting Fish. It is a variation of Betta Splendens with an arrow line pattern similar to the original Koi Fish.   They are usually similar to other betta variations. But their excellent colorings lead to significant health problems for them.   If you are passionate about learning how they are and how to take care of Koi Bettas, keep reading further.

Koi Betta Features

Koi Betta is a variation of Marble Betta. These variations are mainly due to jumping genes. This phenomenon of gene jumping is also called Transposons.

During gene jumping, the DNA pieces actively move from different places of the genome of an individual cell. This would result in a change in the color of the Fish. It also causes an increase in the pigment intensity of the Fish.

We can’t be seen in the wild as they are Betta splendens selectively breed under man-made conditions. Betta splendens are the origins of stagnant rice fields and swamps in the southern and east Asian parts.

Marble Bettas

Koi betta fish, Marble betta fish
 Marble Bettas are of various types.

  • Galaxy betta
  • Fancy Betta
  • The popular Nemo
  • Koi Betta

Though they differ by color, Koi Bettas are Betta Splendens. So, Koi Betta fish must take them at most care like the other Betta types.

Koi Betta Identification

These Cute little ones change colors quickly. But, it is not that difficult to spot them. Usually, Bettas have a uniform pattern of Red, Black, and orange on their White Body. This is a crucial feature of the Betta Variants. They are also Short-tailed in nature.

How big does Koi Betta Grow?

Koi betta fish, Big koi betta fish
Koi Bettas usually grow around 3 inches long. But they don’t usually have the additional space for their fins to grow much longer. Koi betta fish is a short-finned breed.

Koi Betta Behavior

Marble betta may have a resemblance to Koi Fish. But they are not like the Koi Betta Fish. They are True Betta Splendens who carry the typical trails of a Betta fish. Even though they are aggressive, Betta fishes are liked by many and are grown in aquariums. They are one of the most active fishes to keep and grow. Koi Bettas fish is more of a social fish that loves to make a relationship with other fishes.

Is Koi Betta Fish Agressive?

Bettas are one of the most Aggressive fishes in aquariums. They are even called the Fighter fish. Koi Betta Fish is also more aggressive than other fishes. The male Betta fishes fight mainly for territories and Female Betta fish. The fights will continue even till their death. Male Betta Fishes at times consider their reflection to be another male Betta Fish and start hitting the glass. So, it is highly recommended not to introduce two Male Betta Fishes in the same tank.

Koi Betta Fish Tank Specifications

It is always better to keep Betta Fish alone in a tank. Most of the smaller tanks will do the job. They also shine very bright colors when kept in single tanks. 5-gallon tanks will be good enough to hold a Betta Fish. It also requires a heater to be fit.

Constant water changes (25% per week) and care are required. Filtration must also be done from time to time. Tanks can be layered with gravel or sand at the bottom. Wanna know more about filters visit our Fishtank Filters post.

The addition of Logs and Fish Tank Decorations can also be done. These decorations will be a great hiding place for Bettas.

Smooth rocks and driftwoods can also be kept inside the tank as decoration and fish hide spots. If you plan to add other species with Betta, Fishtank must be at least 15 gallons in volume. At times, Betta may not even accept other fishes in their territorial tanks.

Tank Requirements

  • Tank Size: Minimum of 5 gallons
  • Water pH: Slightly basic 6.5-7.5
  • Water temperature:73-75° F

Koi Betta Fish Diet

Only at the best of their health, Koi Bettas will be radiating their beautiful colors. So, Siamese Fighting Fish must feed them with High-Quality Diet. Bettas eat both Vegan and Meat in wild habitats. In-tank conditions, they prefer more to be carnivores in nature. High protein food like flakes and pellets must be your pet betta’s diet. Brine Shrimps and Bloodworms shall be given weekly. Bettas prefer to be more specific in what they eat. So, it won’t be easy to find what your Betta wants to eat. But once if you see which pellet you Betta loves the most, then feeding becomes easier. Overfeeding or feeding more larger pieces may trouble Koi Betta’s digestion. This may cause constipation and even Overall weighting.

Marble Betta (Koi) Diseases

Due to manipulated breeding, Koi Bettas are easily prone to diseases. Morphological problems are also common in this breed. Swim Bladder disease and Fin Rots are widespread in Siamese Fighting Fish. This is easily treated by standard medication. Tumors are also more likely in Koi bettas due to mutation of DNA. Tumors can be spotted by an abnormal growth on the surface. But not all those lumps can be called a tumor. Internal tumors may also occur in Loi bettas, and it is hard to be diagnosed. Lumps may also be due to bacterial infections or ulcers. They can be treated by quarantining larger lumps are treated only surgically. But this will also be highly risky for the Betta.


Marble bettas are a wonder in the betta community and always a treat for the viewer’s eyes to watch. If you are interested in keeping Betta Splendens in your aquarium, then you can surely go for it. But make sure you both fighters meet the other head to head!!


How much does a koi Betta cost?

Bettas are lovely fishes, and buying a Betta would cost you between $4to 20$. The price of a Koi Betta Fish is around $5-10$. The price may go even up if you are looking for rarer kinds of bettas. 

What is the rarest betta fish?

Fan-Tail Bettas are the rarest of all Bettas. They look similar to a fantail goldfish. They are very rare, and even the information about Fan-tails online is very little compared to the popularity of other well-known betta varieties.

How long do koi betta fish live?

Koi Bettas can live up to 3-3.5 years when kept under better water and optimal conditions. This is usually a shorter lifespan when compared to other fish varieties.

Know more about fish lives at average lifespan of tank fish blog.

Are Koi Betta smaller?

Koi Bettas belong to the Betta Splendens variety. They usually grow up to 3-3.5 inches.

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