Betta splendens or the ‘Siamese fighting fish’ is one of the best known aquarium fish in the world. Its colourful, long fins and modest needs make it an attractive pet for many people. It’s mostly known for its aggressive temperament and will to fight, which is how it gained it popularity. But it didn’t start with this sometimes little extravagant big colorful fish, it started with its grandparents, the wild betta splendens. Wild Betta splendens are the most similar to our domestic bettas and are the base of the genetic structures of the well-known domestic fighting fish we all know.

Some background

Mostly the genus ‘Betta’ or ‘Betta fish’ is solely used to indicate the species of Betta splendens. The domestic Betta splendens is often referred to as ‘Siamese fighting fish’, referring to the aggressive temperament and origins as fighting fish in Siam (now Thailand).

In this article we will refer to the domestic betta as ‘domestic Betta splendens’ and to the original wild Betta splendens as its scientific name.


The name ‘Betta’ is a derivation from the local word ‘ikan bettah’. In 1910, Betta splendens was described first by a scientist who named it Macropodus pugnax. Later it was renamed as Betta splendens by Charles Tate Regan.

Betta splendens is part of the B. splendens complex, along with Betta smaragdina, Betta mahachaiensis, Betta stiktos, Betta imbellis and Betta siamorientalis. The domestic betta has been created out of several species out of this complex, with the base of its genetics being Betta splendens.


There is a lot to find about the history of the domestic betta and you could write a book about it, but in order to keep this article focused and not too long I’ll keep this as brief as possible.

In the beginning of the 19th century and possibly much earlier, people were collecting wild bettas (mostly B. splendens) to fight for them. People bet on which male would win in a fight in a small jar. After a few minutes the males were separated, but sometimes they had to fight until death. But bettas gained their biggest popularity when the king of Siam (now Thailand) showed his interest in the fish. He later gave some fish to dr. Cantor who first described them as Macropodus pugnax.

Only in the 1900s bettas were started to be imported in the western aquarium world. People started breeding them and so many different colors and strains have been developed.

Betta splendens habitat

Betta splendens is the most distributed species in the splendens complex. It lives in the northern provinces of Thailand such as Chiang Mai, throughout whole central Thailand around the Chao Phraya basin. It also occurs in the more southern parts of Thailand in and around the province of Surat Thani.

There are many sightings of Betta splendens in other places, such as Sumatra or in Loas, but those are a result of human distribution.

Domestic strains have spread around the globe, to parts of Florida, Brazil and Australia as an invasive species.

A wild Betta splendens habitat. Photos by Frank sriboribun.

Due to all the organic material on the bottom which add tannins to the water the water is mostly sour. In wild habitats pH is in between 4.5 and 6.q

Endagered status

Although the domestic Betta splendens have gained an enormous popularity around the globe and enjoy success in captivity. Unfortunately, its wild Betta splendens siblings are in danger due to loss of habitat and humanly caused problems. Habitats are being destroyed for mostly agriculture and industry.


Bettas will flair at basically anything. A very useful video on how to flair train your Betta splendens.

Bettas have gained their popularity partially by their remarkable behaviour towards each other. Even people who don’t have any fish will know these fish because of their temperament. The will of males to face off to each other and fight, even until death if no other way possible. This made them an attractive fish for local communities for gambling and so people started breeding them.

Males will flair to anything seen as either a threat, or females who they want to impress. They put out their gills to appear bigger and spread all their fins in order to look bigger and more impressive. This makes them not a great choice to place in busy community tanks or with each other.

Appearance of Betta splendens

Betta splendens is a dark-brown couloured fish with blue-green accents all over the body. In contrast to its siblings from the Betta splendens complex such as Betta imbellis and Betta smaragdina it has way less scaling in the bottom half of the body. The most vibrant thing is the red colouration on the anal and caudal fins. Its ventrals are red with black borders.
When agitated, bettas get more colourful and will express their colors to show off at either the opponent (other male) or to impress the female.

Betta splendens
A very red Betta splendens male. © Frank Sriboribun

Betta splendens might be confused with Betta imbellis, which have red colours on the same places. The main difference is that Betta imbellis has an intense green color and more scaling all over the body. The red on the caudal fin forms a round eclipse, while those of B. splendens forms a less delineated stain.

Males get bigger than females, up to a good 2 inches. Females stay smaller will get no bigger than 1.8 inches.

Wild Betta splendens vs. Domestic Betta splendens

Wild B. splendens right (© andre on flickr) and Domestic betta splendens on the right

If you have kept bettas for a while, you might wonder what the difference between the wild Betta splendens and the domestic Betta splendens are.
First off, the domestic betta is a hybrid species. The name ‘Betta splendens’ has been given to it because it makes up the bigger part of its genetic structures. But it’s almost sure that it has been bred to otter species within the splendens complex to gain certain characteristics.
The domestic betta is therefore a hybrid, and the wild Betta splendens is a pure fish, except for the exceptions of some humanly made derivations.

As of outer appearance, it is pretty clear what the differences are. There are dozens of color variations in the domestic betta such as crowntail, halfmoon, plakat, etc. All these fish have extensive colors and are bigger than the domestic Betta. Sometimes halfmoon or veiltail bettas can reach up to 4 inches in length with their fins included, whereas all wild betta fish stay way smaller.

Left to right: halfmoon, veiltail, crowntail, (halfmoon) plakat

Many people claim wild betta fish are more peaceful than domestic bettas. You will need to be careful however on how you interpret this. If you have read some articles on bettas in general, you know bettas can’t stand each other, especially males. To say that this isn’t the case with wild bettas, is not true at all. I would say wild Betta splendens is a very aggressive species and will not hesitate to fight other congeners. That being said, if you house them right you can have a bigger chance of keeping them together permanently than with the domestic betta. Scroll down to keeping bettas in pairs for more.


If you want to keep wild Betta splendens, you will need to read up a little on how to care for them, since there is a little more to it than caring for your regular betta. Don’t worry, nothing too fancy :). If you read and follow these guidelines, you should be ready to care for your wild betta. This part is focused on how to care for wild betta splendens, if you want more specific info on how to care for domestic bettas (although these tips will benefit your domestic Betta too), I’d suggest reading betta fish care.

In order to provide your Betta splendens with the care it needs, you will first need to set up a tank that mimics its natural habitat as best as possible. If you read the habitat part, you know Betta splendens’ wild habitat consists mostly of plants and organic material.

Plants & cover

I will always say that alive plants are the most important thing in your aquarium. Apart from making your tank more beautiful (subjective) and certainly more natural, they improve your water quality drastically and provide useful shelter where your betta fish can feel safe. Some good plants for your betta tank are Anubias sp., java fern, java moss, Cryptocoryne sp. and floating plants such as frogbit.
Hardscapes are great to add extra shelter and many good plants such as Anubias and java fern. Wood adds tannins to the water, too and bacteria will benefit from this. If you choose to add rocks make sure you don’t choose those without chalk, since it will higher the pH. Another very important factor are leaves who add tannins to the water. The most known, and my favorite are catappa leaves. They add tannins to the water which benefit the health of your fish, lower pH and hiding places. Some alternatives are alder plugs and oak leaves.
Dried catappa or Indian almond leaves


For a single male, a tank of 4 gallons to 10 gallons is fine. A tank too big will be harder to maintain for a single male and will result in the male more hiding. For a pair, your tank should be at least 20 gallons long. Make sure you always have a lid in place. IT keeps the temperature of the water the same as the temperature of the air. This is important for the labyrinth organ of your betta since they breathe from the air. But maybe even more important is that a lid prevents them from jumping. Wild bettas are even better jumpers and can fit through the smallest holes.


Adding a filter is your own preference. It isn’t necessary but can be great for your plants and other fish. If you decide to put one in, choose one with low volume. Bettas don’t like fast-flowing water. The best option for bettas is a sponge-filter.

Keeping Betta splendens in a community tank

Keeping your wild betta fish in a community tank isn’t recommended. A tank with a lot of other fish will cause stress with your wild betta fish. Betta fish in general need their own personal space and wild Betta splendens even more. In order to prevent too much stress or other fish from getting hurt by your betta it’s best to give them their own tank. Read Betta splendens tank mates for more.

Keeping Betta splendens in pairs

However it is the most safe to have your fish housed alone, but you can have a good success in keeping your bettas in pairs or harems. Betta splendens is one of the more aggressive species in the splendens complex, in contrast to Betta imbellis who is a more calm species.

But there is more to it than just setting up your tank and hoping your pair lives together a happy and healthy life. Like stated before, the first thing is a tank big enough. At least a 20 gallon long for a pair. Bettas prefer a low water level and this creates a bigger surface where your bettas can hide from each other if necessary.

Plants are again the most important component in your tank. They create separated ‘puddles’ (just like in the wild) and make it easy for the males to claim territory and females to be in their own preferred spot.

A watching eye is necessary, and even with the best tank there are no guarantees you can keep them in pairs successfully.

Betta splendens tank mates

However it isn’t recommended to keep your Betta splendens in a community tank, there are certainly fish who you can put with your fish. It is important to know that every betta is different, some do just fine with other fish around and some will be stressed and don’t like it. But with some good preparation you should be able to have some calm fish with your betta. 

If you want to add tank mates, a tank of at least 8 gallon is recommended. This gives your betta male some personal space and his own territory which he can hang out, without having the stress of fish bothering him. Fish you can keep with bettas have to be calm and peaceful. This is why barbs or gouramis aren’t a good species. My absolute most favorite tank mates are shrimp, they are easy, clean up your tank and will not bother your betta.
Some other good species are neon tetras, small corydoras species (depending on your tank size) and other rasbora species. Most small nano fish will do fine too.

Water parameters

Betta splendens are pretty tolerant of water parameters as long as they are stable. You should aim towards a pH of between 6 and 7.5. Other parameters such as KH and GH are less important. If you have bought wild caught fish, you will have to be more attentive towards these values, since captive bred animals are more used to these water parameters and in the wild habitats pH is lower than 6.


Breeding behaviour is similar to that of the domestic betta. You will need to have a tank more covered up with cover such as plants and leaves than normal. What I find is that they are very fast and can swim across your tank faster than with domestic bettas. So, your female will need to have enough hiding places.

Choosing your pair

I always put this part first since I think it’s an important part when you’re thinking about breeding. Choosing a pair is a fun job since you can choose to spawn to fish out of your personal interests. Many people however want to ‘experiment’ in cross-breeding different species. I would hardly recommend only breeding wild Betta splendens to wild Betta splendens. This prevents even more hybrids from coming into our hobby and otherwise there will be more hybrids than there are pure wilds.

Tank setup

One of my breeding setups

After you have chosen your pair, you can set up the breeding tank. A tank between 10 and 15 gallons will do the job. This size gives them enough space away from each other until they are ready for spawning. A water level of 5 to 10 inches is recommended. Apart from giving the pair extra hiding possibilities, it will be much easier for the male to get eggs or larvae from the bottom if they are fallen from the nest.

Cover the breeding tanks with as many plants and cover as possible. Add a couple of catappa leaves, these will make the water brown and add tannins who are beneficial for the fry. Sinken leaves also provide shelter and dry leaves a great support for the bubble nest.

Conditioning your pair

After setting up the tank you can start conditioning the fish. Conditioning gives both fish extra strength and makes them ready for spawning. Start feeding live or frozen foods 1-2 times a day for at minimum one week. In between you could show the pair off to each other for some minutes to stimulate breeding behaviour.
After this week, the male can be added to the breeding tank. If done well, he will build a bubble nest in a couple of days. While the male is building his bubble nest you can add the female to the tank in a bottle or any other kind of transparent tub. This makes the pair see each other for 24/7 and prepares them for spawning.

Betta imbellis female ready for spawning. The white part are all eggs.


If the male is ready for spawning, there will be a big bubble nest. If the female is ready, she shows heavily vertical markings and a clear egg spot (white spot between ventrals).

Then it’s time to release the female. It is normal if there are little fights sometimes, but not if they fight constantly. This is why cover is important. A spawning will mostly not happen in the first hours and on average will take one to two days. If the pair doesn’t spawn after three days or both parties fight constantly and are in danger, the pair should be separated and reconditioned.

Rasing the fry

If the pair has spawned, remove the female ASAP since the male will see her as an intruder. If you can see very small white dots there are eggs. Don’t feed the male, he will take care over the eggs. When you can see small fry swimming horizontally it’s time to carefully catch the male. Feed the fry with vinegar eels and later with baby brine shrimp and after that with other live foods.

Photo by Sarah Brigham on Flickr.


Just like with any other fish, you will need to do regular maintenance on your tank to keep your fish healthy. Bettas produce waste which is partially processed by your plants and your filter, but regularly water changes should be done to remove nitrites and nitrates which aren’t processed. 

The smaller your tank is the more water changes it needs. I would suggest doing water changes of 80% at least once a week. Doing water changes is a feeling too. If you are experienced you will know when and how much to change water. There aren’t any fixed rules on how and how much to change water, and sometimes the tanks who don’t follow the rules are the best ones.

Final thoughts

Betta splendens is an amazing species if you are searching for a new challenge or something different than the domestic betta. You will need to be prepared to give this species a good home. It is pretty agressive and although many say so, keeping them together is risky. Feed them with a variety of foods, put them in a good sized tank with plants and a tight lid and you will enjoy a beautiful fish.

Do you have experience in keeping Betta splendens? Let me know what you think in the comments!