Betta falx

Betta Falx: A Complete Care Guide on This Beautiful Fish

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When we hear of betta fish, most of us immediately think of the iconic Siamese fighting fish, Betta splendens, with long, flowing fins and exotic colors.

But did you know there are nearly 70 other species of betta fish besides them?

One of them is Betta falx, a lesser-known species that will charm you with its elegant beauty and fascinating behavior.

What’s more, this type of betta can even be kept in mixed groups! Now there’s something worth finding out more about…

Fact Sheet Info for Betta falx

Betta Falx Info
Common NamesSocial Betta
Scientific NameBetta falx
Minimum Tank Size5 to 10 gallons
Experience LevelIntermediate
Lifespan3-4 years
DietOmnivore but primarily carnivorous
AggressionMostly peaceful
Water temperature72° to 80°F
pH levelPH 4.7 to 6.8
Water hardness4 to 8 dKH

Natural Habitat

All betta species are from Asia, but Betta falx is from a little further south than Betta splendens – it hails from the lush rainforests of Sumatra.

This fish loves to hang out in dense vegetation in the shallow waters of swamps, shallow streams, and pools under the thick undergrowth of the forest. The water is often brown and acidic due to the high leaf litter volume.

These almost-stagnant water conditions need some special adaptations to survive! Like other betta species, it uses its labyrinth organ to inhale some of its oxygen from the water’s surface. In the wild, it can even survive in a couple of inches of water!

What Does Betta falx Look Like?

Betta falx is more modest in appearance than the typical pet betta fish we’re familiar with. Its fins are much shorter, and its body color ranges from brownish-grey to brownish-red. Its beauty is rather more subtle and understated than the flamboyant Betta splendens!

Its shape reminds me of gourami, which isn’t surprising, considering bettas and gouramis are closely related. It’s much smaller than any gourami, though, with a maximum size of just 2 inches.

The male also has larger fins than the female, with stunning iridescent blue tints on the anal fins and sometimes on the head.

Related Species

Betta falx is closely related and easily confused with other similar wild betta species.

Betta picta, Betta taeniata, and Betta simplex come from the same picta subgroup and can be distinguished by the subtle differences in their fin shapes and colors.

The Lifespan of Betta falx

The Betta falx typically lives for up to 4 years in an aquarium, similar to the life expectancy of Betta splendens.

They are often less than 7 months old when you buy them at the store, sometimes only an inch long. Always look for healthy specimens with bright, shiny fins, scales, and eyes.

Betta falx Care Guide

Tank Size

Like most other bettas, a single Betta falx can be kept in at least 5 gallons of water. But since this species can happily live in a group, most aquarists will choose to host several of them.

A single male and female pair would do fine in a 10-gallon tank. For a larger, mixed group of three females and two males, you’d need at least a 20-gallon tank with plenty of hiding places to prevent territorial aggression and excessive rivalry.

Water Parameters

Betta falx is tolerant of slightly cooler water than your typical betta. Anywhere between 72-80 Fahrenheit is fine.

This fish will be most happy if you can replicate its ideal natural environment. In the leafy pools of Sumatra, the water is soft and acidic. A pH of 4.7 – 6.8 and a hardness of 4-8dkH will help this fish feel at home.


Like other bettas, Betta falx requires a good filter but won’t appreciate a strong current. Try to find a filter with a gentle flow or at least an outlet that can be directed to the lower reaches of the tank.

This will provide a more tranquil environment in the tank’s upper reaches, where this species will spend most of its time.


Once again, we have to think about this fish’s origins. The light is quite diffuse way down, under the dense canopy of the rainforest.

It is better, therefore, to offer Betta falx a low level of lighting or at least some floating plants that will help to dim most of the aquarium.

You can check out this guide to various floating aquarium plants here.


Since this betta enjoys a densely planted tank, aquarium soil would be a good choice of substrate.

Soil is the ideal consistency for root development and contains all the necessary nutrients for your plants to grow vigorously.

Gravel is an acceptable second choice, perhaps with some fertilizer tabs to help the plants along. 

One of the slight drawbacks of soil is that some brands tend to make the water more alkaline than this fish would prefer. This could be remedied by the addition of Indian almond leaves.

Indian Almond Leaves

You can remedy alkaline conditions in the aquarium with the addition of Indian almond leaves, which are now readily available to hobbyists looking to duplicate the natural water conditions of their fish.

The leaves lie at the bottom of the fish tank and slowly release tannins, making the water darker and more acidic. They are also said to have anti-fungal and antibacterial properties that help keep your fish free from disease.

Indian almond leaves may be especially useful for the Betta falx, which will feel more at home in acidic, darkened water, with leaf litter among the substrate.

Read more about the potential benefits of using Indian almond leaves here.

Tank Decoration

Betta falx swims among a dense tapestry of aquatic plants, fallen branches, and twisted tree roots in its natural habitat.

You can replicate this exotic jungle environment by offering driftwood and suitable plants to swim among.

Suitable Plants

Since Betta falx demands low light levels, it’s important to choose plant species that can grow with a restricted amount of lighting too.

Microsorum pteropus (Java fern), Taxiphyllum barbieri (Java moss), and Cryptocoryne spp. (Crypts) are all good choices.

As previously mentioned, you could combine brighter lighting with floating plants like Limnobium laevigatum (Amazon Frogbit) to create attractive dappled shading, with shade-tolerant plants growing underneath.

What To Feed Your Betta falx

The Betta falx is much closer in its genetics to the wild species than the more heavily domesticated Betta splendens.

Since they haven’t undergone centuries of captive breeding, they may be a little slow to recognize dried food as food!

While they may learn to like betta pellets over time, they will do much better on a diet that includes plenty of bloodworms, brine shrimp, and daphnia.

Remember that bettas are primarily carnivorous and therefore need specialized high-protein foods. Never try to give this wild species ordinary ‘complete’ fish foods since they simply don’t have the necessary digestive setup to process terrestrial carbohydrates like wheat and corn.

How Much and How Often To Feed

A betta’s stomach is no larger than its eye, and its digestive tract is very short. This family of fish is also notoriously greedy!

All of this means that it’s really easy to overfeed bettas. Bloat, digestive disorders, obesity, and tank pollution are the likely outcomes.

Betta falx is best fed once or, at most, twice daily. Remove any uneaten food at the bottom of the tank unless you have included some peaceful bottom feeders like a Cory catfish or Khuli loach to do that for you!

Good Tankmates for Betta falx

The Betta falx is a small, timid species. They definitely won’t appreciate larger, boisterous tankmates like swordtails or mollies.

They can, however, be kept quite successfully alongside peaceful, smaller fish such as White Cloud Mountain minnows and Raspboras, as well as self-contained bottom-dwellers like Cory catfish, plecos, and Kuhli loaches.

The great appeal of this species is that they can be successfully kept with one another…

Keeping a Group of Betta falx Together

If you’re looking for great tankmates for Betta falx, look no further than other Betta falx!

Unlike Betta splendens which will rip one another to pieces given half a chance, the Betta falx is far more peaceful and kind towards one another.

Males and females can be kept together permanently, and even multiple males can be kept in the same tank so long as they each have adequate space and places to hide.

Behavior and Aggression

Their tolerance of one another is one of the great assets of keeping this species since the interaction between individuals can be fascinating!

Their behavior around courtship is especially captivating, as males jostle for a position to mate with a female.

Although they will flare and chase one another at breeding time, they will not tend to pursue the loser of a contest. The submissive male will merely retreat among the undergrowth you have thoughtfully provided for him. The victor is then allowed to mate with the female – another delightful encounter.

Breeding Betta falx

The possibility of breeding a rare species like Betta falx is another great incentive for keeping this fish.

Like all bettas, their courtship ritual is a wonder to behold, but better still, the males and females of Betta falx can be kept permanently together.

If they turn out to be good parents, they can be kept alongside their fry, meaning there’s no need to swap fish in and out of the tank during their breeding period.


In a mixed group of Betta falx, the courtship will begin with the males sparring gently with one another to decide who will get to mate. The dominant male will then ’embrace’ the female repeatedly until she releases her eggs for him to fertilize.


Betta falx is a mouthbrooder, meaning that the male keeps the fertilized eggs in his mouth for 9-12 days until they hatch.

Once the tiny fry hatch, they will be at the mercy of other tank members predating them, which will also cause the parents stress. Sometimes in a panic, the parents will even eat their own young.

Therefore, if you want to give the fry a good chance of making it until adulthood, it’s much better to give a brooding pair their own tank.

Rearing the Fry

Unlike some other betta species, the parents can often be kept safely alongside their young so long as they are relaxed and happy. This means providing them with the same familiar, cozy environment described above.

If the parents are known to eat their young, an empty breeding tank could be arranged, with the parents removed after the fry are free-swimming.

The fry is best reared on micro worms and occasional brine shrimp, alternating foods twice a day to offer them the best nutrition.

One Last Note on Caring for Betta falx…

As with other wild bettas, this species is an exceptional jumper! Be sure always to keep a tight lid on your tank to prevent any disasters!


Although not nearly as common as Betta splendens, Betta falx is relatively easy to source compared to many other wild species.

Since they breed so easily in captivity, there are often more offspring than an owner can accommodate, meaning they often get redirected to pet stores. You can find these unique fish for as little as $5 each.

Is the Betta falx the Right Betta for Me?

While the Betta falx is one of the easier and more peaceful of the wild bettas to keep, some challenges are still involved in keeping them.

Their fussy diet and the strong preference for a heavily planted tank mean you’ll definitely need some aquarium experience to take good care of them.

If you feel qualified and are ready to host or even breed a rare and intriguing wild fish, then Betta falx might be just the right fish for you! Good luck!

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