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Betta Falx

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Aug 12, 2003
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Warm and Sunny Arizona
Common name/s: Betta falx

Scientific name: Betta falx

Family: Osphronemidae

Origin: Indonesia

Maximum size: 1.5in (3.5cm)

Betta falx are one of the more commonly available wild-type Betta species in the aquarium hobby. They are a small, hardy, mouthbrooding fish, from the Picta Group or Complex, and can be kept and bred quite easily and successfully.

They hail from Indonesia, where they are found in quiet, stagnant waters with submerged vegetation. The water usually has a pH of 4.7-6.8, though in the home aquaria they easily acclimate to higher pH levels (I keep mine at pH 7.6, and they have even spawned at this level). Temperatures should be around 72-79 degrees F (22-26 degrees C).

Housing requirements are quite simple for this species. A basic 10 gallon US tank is sufficient for a pair. For larger groups, a larger tank will be needed. Tank decor should include "caves" (usually the inexpensive terra cotta pots you can find at local craft shops will do the trick, I even use clean shot glasses covered with gravel), plenty of plants (live or fake, its up to you), a simple sponge filter (it is fry-friendly), and of course, a tight fitting lid (falx, like all bettas, are jumpers).

Wild-caught varieties may be more picky initally but many keepers have found they DO adjust to most foods. But tank-raised falx will pretty much eat anything. I have even gotten mine to take flake food readily.

Betta falx, in general, are your typical mouthbrooding betta in that they spend much of the their time hiding or holding fairly still, until food falls in front of them. At that point, they will charge out and gobble it up. Though, as I have found, they are not above coming to the surface as well to eat, rather than waiting down below for the food to fall. Some foods of choice would be frozen brineshrimp, frozen bloodworms, frozen daphnia for the youngin's, as well as a variety of live foods.

Betta falx can be difficult to sex, especially when juveniles. Both males and females have a light brownish body with three black, horizontal stripes down the length of the body. The central stripe starts at the snout and crosses over the eye (the eye often almost blends into the line, giving them an interesting look). When courting and spawning, the stripes will become even more prominent. Along with that, the male's anal and caudal fins will color up a nice red-brown, and the blue and black bands on the anal fin also become more prominent (refer to male photo below).

Most falx keepers/breeders will tell you that falx are like rabbits, breeding constantly. Many find they actually have to separate the sexes when not planning on a spawn. The female is usually the one who gets the party started bychoosing a male and chasing off any other males or females. You will see some courting behaviors which I like to call "falxy-flirting." The male will display his fins and his color will deepen (see the male photo below, taking during courtship). The female will do her own dancing about, and each will "present" themselves, nudging, pecking, and rubbing past each other. When they are finally ready to spawn, the male will "embrace" the female, basically wrapping himself around her. They line up their vents, and as the female releases eggs, the male fertilizes them. The female will then pick up the fallen eggs and spit them at the male, who will catch them and hold them in his mouth. He will stop taking them in when his mouth is full.

At this point, unless you have them in a large or divided tank, it is best to remove the female. If she is allowed to stay, she is likely to try to get him to spawn again and he may spit/swallow the eggs before it is time for release, resulting in the loss of the spawn. (B. falx will usually attempt to spawn about every two weeks)

The male will now "hold" the eggs in his mouth anywhere from 7-14 days, until the fry reach maturity. Then the male will release the free-swimming fry. During this "holding" time the male will become less active, stop eating, and hide out more than usual. You will notice him turning the eggs from time to time in his mouth, quite a sight.

I have found B. falx to be a great starter fish for folks interested in keeping mouthbrooding wild-type bettas. The males displays wonderful coloration during courting, and their whole courting and spawning ritual is something you don't want to miss. I have found my two pairs to be bold and quite the attention pigs, rather than being shy and skittish like so many wild-type species.They are very active little fish and a joy to watch and own.


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