Betta falx
Tan & Kottelat 1998

Betta falx male
Photo by Kei Sasaki (Betta House) [5]

Keeping Betta falx from an Aquarist View


Betta falx can be housed in pairs, species tanks, and community tanks.  Pairs can be housed in a 2.5 gallon tank, groups should be housed in a 10 gallon tank or larger.  Pairs should be given cover such as caves and plants.  In a pair or species situation it is possible that fry could be discovered in the tanks.  For best results remove a brooding male.

Water Conditions

Not critical, falx 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 cool to mid 70s F.


Males have a broader head then females and a much darker stripe on the anal fin.  Females may not have a stripe or faint stripe on the anal fin.  Females ovaries might be visible via spotlighting.

Betta falx male
Photo by Kei Sasaki (Betta House) [5]

Betta falx female
Photo by Kei Sasaki (Betta House) [5]


Falx is a paternal mouthbrooder and the male incubates from 9 to 12 days with 10 days being very consistent.  Incubation time can vary with water temperature.  Females normally initiate spawning.

Similar Species Similar species would be picta complex members simplex, picta and taeniata.
Identification Falx males normally do have a highly pronounced stripe in the caudal fin like simplex where as picta does not.

Articles on Betta falx

Care and Breeding of Betta falx Gerald Griffin 2003, Republish from Flare Magazine

Articles on related species

Betta picta: Not Very Beautiful, But Interesting NonethelessGerald Griffin, 1988 Republish from Flare Magazine

Betta picta (Sumatra)  Yohan Fernando

Betta picta – Carolyn Hanlon, 2007

Original Citation Tan, H. H. and Kottelat, M. 1998. [101]
References Tan, H. H. and M. Kottelat, 1998. [103] Froese, R. and D. Pauly, 2002. [126]
Collection Data 22 Jun 1995 Sungai Alai, km 19.5 on Muara Bungo-Muara Tebo Rd., ca. 1°28’42.6″S, 102°18’31.7″E, Jambi Prov., Central Sumatra
Holotype MZB 9308
Paratype CMK 11119 (44)
MHNG 2593.95 (5)
MZB 9307 (4)
RMNH 33087 (5)
ZMA 121673 (6)
ZRC 38254 (3) 38571 (44), 40974 (20), 42496 (10)
Where Found Countries: Indonesia
Known Occurrences: Indonesia: Sumatra: Jambi Prov.: Sungai Alai, km 19.5 on Muara Bungo – Muara (1 28.72 S 102 18.53 E)
Miscellaneous Information Max Size: 3.49 cm SL
pH range: Typically found among submerged bank vegetation, in near stagnant waters, with pH 4.7-6.8.
Etymology: Latin, falx means scythe, alluding to the continuous curved shape of the broad anal and caudal distal margins of a male in display.
Caudal fin rounded. [126]
Locality: Hari river basin, Muara bungo, Jumbi, Sumatra. [6]
Water quality: pH 5.7/GH0-1/KH0-1/TDS30/ lightbrown water [6]