Betta splendens (Siamese fighting fish) Ultimate Guide

betta splendens

Betta splendens (Siamese fighting fish) Facts

Scientific name: Betta splendens
Common name: Siamese fighting fish
Family: Osphronemidae
Origin: Native to the Mekong basin of Thailand, Cambodia, Laos, and Vietnam and is mostly concentrated in the Chao Phraya river in Thailand
Usual size in fish tanks: about 5.5 to 7cm (2 to 2.7″)
Recommended temperature: 24 – 28 °C (75 – 82°F)
Recommended pH range for the species: Ideal levels for Bettas would be at a neutral pH (7.0)
Recommended water hardness (dGH): 10 – 15°N (0 – 214.29ppm)
Aquarium: You can only have one male in Aquarium since they do not get along. Although you can have two females in the same tank, it’s advisable to avoid it. It’s also advised to avoid having any other fish species in the tank since Betta splendens tend to be a bit aggressive towards other species.
If space is an issue, you can house young Betta splendens with other species. The young fish can sometimes accept other species in their tank. Once they reach adulthood, you should move them. You should get a 20L tank or larger tank. Make sure you build in caves and add plants for the pairs.
Tank preferences: Middle levels
Water Conditions: Betta splendens is very tolerant of water chemistry and thrives in almost any type of water as long as it is clean and well filtered. They should be kept at around 28°C (82°F).
Reproduction & Sexing: You will find breeding Betta splendens very easy. Betta splendens is a surface bubblenester. The males usually nest under objects on the surface of the water. You should add some floating plants or styrofoam to the tank for the male to use to construct his nest.
The Betta splendens spawning is initiated by males to attract females to the nest for spawning. The fish then embrace each other with the male biting the female’s fins and wrapping around here. This triggers the female to release eggs which the male Betta splendens then fertilizes.
You can differentiate males from females mostly by their color – Betta splendens have a sexual dimorphism which results in diffent colors for the sexes. The males are more colorful and develop more ornate finnage while the females are rounder bodied compared to males.
Temperament to its own species: aggressive
Temperament toward other fish species: aggressive
Lifespan: The expected lifespan for Betta splendens is between 2 – 6 years. With good care and feeding you could extend their life.

Betta splendens (Siamese fighting fish) Generalization

Betta splendens are anabantoid fish which means they have a labyrinth organ that allows them to breathe air from the surface.

That is why you can have them in smaller aquariums which yield low oxygen.

The Siamese Fighting fish males are very aggressive towards their own species and other species as well. You should therefore avoid mixing them in the same aquarium tank.

There are several Siamese Fighting fish which have been interbred and come in different colors. Below are a few types:

  • Standard
  • Longfin
  • Crowntail
SAD: Betta splendens fighting

Betta splendens (Siamese fighting fish) Distribution and Habitat

The native habitat for Betta splendens is in the Mekong basin in Asia.

Betta splendens

Wild Betta splendens occur in rice paddies, flooded plains, canals and in the bank vegetation of both large and small slow moving rivers and always in shallow water. They live in dense vegetation where they move amongst the leaf litter looking for their prey.

The Siamese fighting fish was first bred in Southeast Asia, not as a food fish, but initially for shows and competitions, later as an ornamental fish in the form of the veiled fish.

They have also been found in the waters of South America, the Caribbean, Africa and Madagascar and even on the Hawaiian Islands where they were disposed of in the waters by aquarists.

The Betta splendens survive under very modest  conditions which include the following

  • Temperature between  24° and 30°C, (75° to 86°F)
  • pH level between 6 and 8
  • gH water hardness between 5 and 19

The Betta splendens evolved with a labyrinth organ which allows the fish to breathe oxygen directly from the air due to rotting vegetation in the water that results in low oxygen levels. This organ has become so important to the Betta that if they are prevented from coming to the surface for a breath they will actually drown.

Betta splendens (Siamese fighting fish) Characteristics, Shape and Color

Just like Goldfish and Koi, the Siamese fighting fish has been kept and bred in aquariums for more than 100 years.


When kept in a species-appropriate manner, our veiled fighting fish are by no means as aggressive as they are often said to be.

A couple can easily be socialized with other species of ornamental fish.

A male with several females can also be kept in the community pool.

The prerequisite for this is that the water temperature does not exceed 25 ° C in order to dampen the willingness to spawn and thus the males’ potential for aggression.

Over the years, the Betta splendens were bred for 2 completely different purposes:

  • In Southeast Asia the Siamese fighting fish is bred for size and strength so that it can be used as a fighter in the popular traditional fish fights. It is understandable that in these specimens bred for competitions, care was taken that the fins remain as small as in the wild form in order to keep the risk of injury to a minimum.
  • For aquarists, veil fights were bred for the largest possible fins and their endless color combinations.

Betta splendens that have been bred

There are a number of species of veiled fighting fish that differ in their body and fin colors and the shape of their fins.

You can distinguish the Betta splendens which have bred on the basis of the coloration:

  • With a color pattern: multicolored, butterfly (fish with different colored stripes in the fins) and marble (marbled fighting fish)
  • Special forms with sail-shaped dorsal fin or heart-shaped or crescent-shaped caudal fin
betta splendens

Wild Betta splendens

You can recognize them by:

  • A monochromatic body with blue and red colored fins
  • The caudal and dorsal fin have a rounded shape
  • The body scales shine metallic blue in incident light
  • The males do not grow larger than 6cm
  • The females remain even smaller with smaller fins and often show two darker longitudinal ligaments
  • You can also recognize the adult, sexually mature females by their white genital papilla

Betta splendens (Siamese fighting fish) Biology and Behavior

When you get the Betta splendens, be prepared for fun! They are generally very active and tend to explore their environs

Male Siamese fighting fish are extremely aggressive to each other and other species.

They tend to relentlessly fight any other male that is in the vicinity. You will notice this aggression when they start to deploy their fins to intimidate their opponent. They tend to tear the fins of their opponents.

NOTE: This is the reason why there were previously used as a sport for fighting sport especially in Thailand and other parts of Asia. WE DO NOT CONDONE ANIMAL CRUELTY!

Betta splendens (Siamese fighting fish) in the Aquarium

Fun Betta splendens Fact?

  • The Betta splendens are not very good swimmers.

How should I set up the aquarium for the Betta splendens?

  • If you have a high volume aquarium, arrange the vegetation in different levels in order to help the fish move
  • Have good landscaped vegetation which will allow the Betta splendens to live perfectly in large volumes where they will find rest areas
  • Make sure the tank has a lid on. Betta splendens are very good jumpers. The lid will also help regulate the temperature
  • They are affected by too much current in the tank. Therefore make sure you buy a minimal filtration system
  • Make sure the floating vegetation does not obscure lighting.
  • Maintain the aquarium water at a temperature close to 24/26°C or 75/79°F. Avoid temperatures below 20°C or 68°F. This will require the installation of a heater in its aquarium
  • Settle for a pH around the neutral of 6.2 to 7.5 and a rather low total hardness (below 12°dGH).
  • For decoration, you can use root or rock without any sharp edges

Betta splendens (Siamese fighting fish) Breeding

How to breed the Betta?

Mandatory requirement:

Because the male Siamese fighting fish only meets the female fish for breeding, you will need additional aquarium tanks:

  • A breeding tank
  • A tank for housing the male after spawning
  • A tank for separating the fry from each other after the age of 3 months (at which point they become too aggressive towards each other)

SOLUTION: Build compartments within a large tank

Ideal age for breeding

It is ideal to breed the Betta splendens when they are young – between 6 and 12 months old.

Preparation for the breeding

  • Change their food and start feeding them with live and varied prey once every two days
  • If you opt for an extra tank, choose a small tank which you can fill with vegetation. Build in a lot of hiding places and some floating plants.
  • Allow the ecosystem to stabilize
  • Add in a good portion of first fry food
  • Partition the tank into 2: one for the male and one for the female but allow water to pass through – This will facilitate the exchange of pheromones necessary to trigger the spawning

Introducing the male to the female

  • Introduce the male into this breeding aquarium and let it get used to this new environment for a few days
  • Finally introduce the female into breeding environment. The male should then begin to build a bubble nest on the surface, between the floating plants. This nest is very fragile so there must be no movement of water that could damage or destroy it.
  • The male will start pursuing the female through the entire aquarium to eventually end up directing it towards the bubble nest. The laying will last a few hours. The female sometimes helps the male to place the eggs in the nest.
How to spawn Betta splendens

After spawning

Remove the female immediately:

  • To avoid any aggression from the male
  • To avoid distracting the male
  • To avoid the female eating its own eggs

The fry hatch within 24 to 48h after egg-laying. They will remain in the bubble nest for another 36 hours.

  • At this point, you should lower the temperature to 27/26°C or 79/80°F
  • When the fry start swimming (normally within 2 days), remove the male and start feeding the fry

Feeding and nurturing the fry

For the first 2 weeks

Feed the fry daily with:

  • Micro-worms
  • Walter worms
  • Banana worms
After the first 2 weeks

Distribute food at least 3 times a day (ideally 5 to 10 times) for the first 3 weeks, and then decrease the rate of feeding gradually.

After the first 2 weeks you can feed the fry with:

Other factors to watch out for
  • Keep the water clean by making small changes of water daily
  • Raise the water level by 5 cm (2 inch)
  • Cover the aquarium as tightly
After 3 months

Isolate the young in their own aquarium/compartment.

The Complete Betta splendens Life Cycle

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