Betta Falx
Betta Falx
Betta Falx
Betta Falx
Betta Falx

Betta Falx

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Betta falx


Endemic to Sumatra, Indonesia. Most collections have occured in the central province of Jambi although it has also been recorded in the more northerly region of Utara.

Populations from the different localities are often labelled as such by collectors/enthusiasts in order to maintain accuracy and preserve pure bloodlines, e.g., Jambi or Sumatra Utara. The type locality is within the Alai River watershed, Jambi.


Typically inhabits forest swamp streams and pools, some of which have been measured at just a few centimetres deep. These are usually shaded from the sun, the dense canopy of branches above meaning very little light penetrates the water surface.

Marginal vegetation also tends to grow thickly. The water itself is often stained with humic acids and other chemicals released by decaying organic material. The dissolved mineral content is negligible, pH quite low and substrate composed mainly of fallen leaves, branches and submerged tree roots.

Maximum Standard Length

40 – 50 mm.

Aquarium Size

An  aquarium with base measurements of 60 ∗ 30 cm is suitable for a pair or small group.


Can be maintained in a fully-decorated aquarium although many breeders prefer not to use a substrate for ease of maintenance. Driftwood roots and branches can be used and placed such a way that a few shady spots are formed.

If you can’t find driftwood of the desired shape common beech or oak is safe to use if thoroughly dried and stripped of bark. Clay plant pots or lengths of piping can also be included to provide further shelter.

The addition of dried leaf litter, with beech, oak or Ketapang almond leaves all suitable, can further emphasise the natural feel and as well as offering additional cover for the fish brings with it the growth of microbe colonies as decomposition occurs. These can provide a valuable secondary food source for fry and the tannins and other chemicals released by the decaying leaves are also considered beneficial.

Like others in the genus this species seems to do best under fairly dim lighting. You could add aquatic plant species that can survive under such conditions such as Microsorum pteropusTaxiphyllum barbieri or perhaps some potted Cryptocoryne spp., and a few patches of floating vegetation would be useful to diffuse the light entering the tank.

Filtration need not be too strong, with an air-powered sponge filter set to turn over gently adequate. Keep the tank well-covered and do not fill it to the top as like all Betta spp. it requires occasional access to the layer of humid air that will form above the water surface, and is an excellent jumper.

Water Conditions

Temperature: 22 – 27 °C

pH: Not as fussy as some congeners. The pH in its natural waters has been recorded over the range 4.7 – 6.8 so provided conditions are on the acidic side of neutral no problems should arise.

Hardness: 0 – 90 ppm


Likely to prey on insects and other small invertebrates/zooplankton in nature. Captive fish will normally accept dried products once they’re recognised as edible, but should be offered plenty of small live or frozen foods such as DaphniaArtemia or bloodworm regularly to ensure development of optimal colour and condition. Take care not to overfeed as Betta spp. seem particularly prone to obesity.

Behaviour and Compatibility

Not recommended for the standard community set-up for reasons already touched upon. It’s requirements and disposition mean it’s best kept alone or with very peaceful species since much bigger or more vigorous fishes are likely to intimidate and outcompete it. Some small cyprinids and loaches that inhabit similar environments in nature are compatible.

It can be maintained in a pair or group and will display some interesting behavioural interactions under the latter circumstances.

Sexual Dimorphism

Males grow larger, possess a greater amount of iridescent scaling on the head, a broader head shape, and more extended fins than females.