Betta smaragdina is a wild Betta species known for its emerald green color, from where it received its nickname ‘emerald betta’ from. Its cheerful temperament and unique appearance make it a fish who is loved by many aquarists. But still it is a fish that is rarely seen, especially compared to its sibling the domestic Betta splendens.

In this post you will learn how to care for your Betta smaragdina and how they differ from the Betta’s we all know.

No time to read? Some quick facts.

TemperamentA cheerful fish. Males are aggressive towards each other and can be towards other fish.
AppearanceIridescent green scaling all over the body. Its scales look like snake-skin and cheek scaling is consecutive
TankWell planted. At least 4 gallon for a single male, 15 gallon for a pair
FoodFrozen and live foods like mosquito larvae, daphnia, BBS, or bloodworms. Or dry pellets/ flakes.
WaterpH: 6-7.5 Temperature: 72°-80°F

Betta smaragdina origins and wild habitat

Betta smaragdina is distributed through the eastern parts of Thailand on the Khorat Plateau, As well as small parts of Laos and Cambodia. Due to human activities it has been spread to the rest of Thailand and even Malaysia. This makes them one of the most distributed Betta species, along with Betta splendens.

Wild betta distribution Thailand and Malaysia

Its original habitat consists of small and often oxygen-poor pools, swaps and rice fields. In those habitats, there are lots of plants and the substrate consists of organic materials such as leaves. This bottom makes it ideal for young Betta’s to hide and microorganisms to thrive, who can serve as food for fry. Due to these conditions the water is very sour and pH ranges from 4.5 to 6.5. Low-oxygen and hot water have made Betta’s evolve into a fish who can get all of the oxygen they need out of the air. The labyrinth organ allows them to extract oxygen, as well as build bubble nests for spawning.

Wild Betta habitat in Thailand
A wild Betta smaragdina habitat. Picture by FranksBettas

Although Betta splendens is best known for its hybridisation and selective breeding, Betta smaragdina has been selectively bred mostly for aggression and many strains have been developed. Just like with most Betta species, they have been hybridised with other species from the splendens complex such as Betta mahachaiensis and Betta splendens. This results in colors and shapes who don’t occur naturally.

A Betta smaragdina hybrid. Most likely smaragdina X mahachaiesnis.

Betta smaragdina appearance

The name ‘smaragdina’ is Latin for emerald, where its name originates from. As the name implies, Betta smaragdina is an emerald green coloured fish, its iridecent blue-green scales form a snake like pattern all over the bottom.. Under cold lighting it can turn blue, but its real colors are green with orange accents.

Along with Betta mahachaiensis, it is the biggest species in the B. splendens group with males reaching up to  2.5 inches in length. Females stay smaller, up to 2 inches and develop less colored scaling and smaller fins.

Betta smaragdina vs Betta mahachaiensis

If you have been looking at some wild species, you may have come across Betta mahachaiensis. In terms of appearance and size, it’s the most similar species to Betta smaragdina, but with some explanation it should be fairly easy to see the difference between these two species. 

The most clear difference between these two species is the scaling. Like stated above, Betta smaragdina has a very snake-like scaling pattern, which continues to the cheeks. Ulike Betta mahachaiensis, who has a black stripe dividing the mask on its cheeks and more plated scaling. The body scaling of B. mahachaiensis is not forming a consecutive pattern and the black background is more clear.

B. mahachaienis (left) B. smaragdina (right credit: FranksBettas)

Subspecies and hybrids

There are two well known variations on the classic Betta smaragdina. 

Betta smaragdina sp. guitar is a naturally formed and subspecies and lives only in the far north eastern part of Thailand. 

What makes them differ from the normal smaragdina are their guitar like markings on the dorsal and caudal fin. As of coloring and sizing they are the same, except for the ventrals who tend to be longer.

A guitar male. Credit: Frank Sriboribun

Betta smaragdina ‘copper’ on the other hand, is a human created hybrid species.

As you can see, it has a copper-brown color. As of anatomy it is similar to the original smaragdina. But it stays a hybrid species and should not be crossed to autentic smaragdina species.

A copper male.


Keeping Betta smaragdina together with other fish in a regular community tank isn’t recommended. Overall, wild betta’s tend to be more shy in community tanks. They can become aggressive towards tank mates or get injured themselves.

In my personal experience, Betta smaragdina is tougher in terms of diseases since they have been less bred in captivity and hold more natural resistance towards classic illnesses. In fact, in the years I kept wild betta’s I never had any disease. The biggest cause of death are jumpers who jumped out of the tank. On the other hand they need somewhat more attention for the tank and the environment such as tannins and plants.

Males will become aggressive towards each other, the fable that if you keep a harem of a couple of females you can have two males, is not true. Males are programmed to fight each other and it will not help to have multiple females to compensate for that. If you want to keep a pair, this is always at a risk, since Betta’s are solitary in the wild and are aggressive towards each other.


Betta smaragdina is a rather easy to care for fish, but some preparation is required if you want to make sure you can get your fish a healthy and happy life.


The perfect tank for wild bettas
Photo by Peter Luijtens

For a single male, a tank between 4 and 10 gallon is fine. Having a tank too big could result in the male not feeling safe. This is because a male will always want to defend his territory and if he can’t defend his part, he is likely to stress out. If you however have a bigger tank, adding enough plants so the tank gets ‘divided’ into different parts, this will do the job too but then it can be that your male will start hiding more.

Wild bettas prefer shaded aquariums over tanks with a lot of lighting. If you have very intense lighting, you can add floating plants like frog bite or water spangles.

In the wild habitats, lots of plants grow. To provide your fish with enough natural cover and keep your water clear, live plants are a must. Think about plants like anubias, java moss & fern, cryptocoryne sp.. To provide some extra shelter and add a natural touch, you could think about adding hardscapes such as driftwood or rocks (without chalch for the pH).

Catappa leaves are a good choice to add tannins to the water. Apart from giving your water a more natural color, it lowers the pH and helps prevent diseases and it provides shelter if necessary.

A filter is not necessary. Low tech setups are fine and adding a filter is personal preference. This can however be beneficial for plant growth and preventing algae. Just make sure your filter doesn’t create a flow too hard. 

Wonder what to do with those algae that are covering up your tank? Don’t worry, they’re not that bad for your fish. Some algae in your tank don’t harm your tank and even add some benefits. Just make sure your tank doesn’t get covered up in them because your plants will die then. It’s up to you what you prefer. 

One of my tanks who is covered up in brown algae on the sides. Plants are growing and the fish love the natural touch.

Tank mates?

Like stated before, it isn’t recommended to keep your Betta smaragdina in a community tank with lots of other fish around them. This doesn’t mean however that you can’t create a habitat where you can have your Betta, as well as some other tank mates with it.

The most important thing is that Bettas like their privacy. Your tank should be at least 10 gallons if you think about adding fish with it. Otherwise, your Betta won’t be happy.

Good inhabitants to live with your Betta are calm fish such as small tetra species, shrimps ( but it can be your Betta will eat some), corydoras or snails.

Keeping Betta smaragdina in pairs.

Although it is said that wild Betta’s would be more peaceful than its siblings Betta splendens. I can confirm that this is for most parts not true. Though it is certainly possible to keep them in pairs, in most cases it will end not so well.

For a pair a tank of at least 20 gallon ‘long tank is required. This is because otherwise female and male will start fighting until death. Add as much plants as possible and use hardscapes like wood to provide hiding spaces.


It is fully carnivorous and feeds on water creatures. In order to provide them with enough nutrients, vitamins and minerals is recommended. Good foods are frozen foods such as daphnia, mosquito larvae, artemia and bloodworms. If you want to give your fish something extra, live foods are a great choice. Sometimes they can be picky towards dry foods like flakes or pellets.


Betta smaragdina isn’t very sensitive towards your parameters, as long as they’re stable. In the wild pH is on the sour side, ranging from 4.5 to 6.5. In your tank you could have a pH of 6 to 7.5, since captive bred animals are more used to these parameters. As of temperature, anything between 72 and 80° is fine.

Screenshot from FrankBettas video. pH in natural habitat of Betta smaragdina.

Breeding Betta smaragdina

Breeding this Betta species isn’t very hard, but you will need to prepare well if you plan on spawning them and afterwards, caring for the fry.

First off, you need to choose your breeding pair. I recommend looking for reputable breeders who can sell you a pair. Watch out for hybrids and always breed smaragdinato a smaragdina. Otherwise the market will consist of more and more hybrids, which causes our wild Bettas to disappear.

In order to prepare them for breeding, the pair will need to be conditioned with a variety of (preferably live) foods to get the female more fed and the male ready to care for the fry.

After conditioning for one to two weeks, the pair will be ready for spawning. Set up your breeding tank while conditioning both fish. A tank between 10 and 15 gallons gives the pair enough space and you can care for the fry in the same tank. Add a lot of plants to give them hiding spaces and make them comfortable.

If you have conditioned your male properly, he will make a bubble nest. Adding a dry catappa leaf helps support the nest. Then you will need to let the pair meet each other. You can do this by putting something like a bottle in the tank where you put in the female. After a couple days of meeting, the female should show heavy vertical markings. 

This is the moment to release the female. Don’t worry if some aggression is shown, this is normal behaviour. But when they are constantly fighting, separating the two is recommended. A normal spawn takes around 1-2 days and females should be removed right after the spawn has happened, since the male will see the female as an intruder. 

After 2-3 days when the fry is swimming, the male has to be removed too. The fry has to be fed with infusioria or vinegar eels, and later baby brine shrimp.


If you are searching for a new fish which you can keep in a small tank with some small other fish or for a new adventure, this is a good and beautiful choice. But there is some more to it than the classic domestic Betta if you want to give your fish proper care. Make sure you have at least a 4 gallon tank for a maleand plant it well with a variety of plants. If you can provide a good environment for your Betta, you will enjoy a beautiful and cheerful fish.