Krabi Mouthbrooder (Betta simplex) Care Guide
Betta simplex is a mouthbrooding wild betta endemic to limestone springs near Krabi, Thailand, unusual for tolerating hard, alkaline water.
Compiled by Aquairi from published sources · Published · Updated
Overview
Betta simplex is a wild betta of the family Osphronemidae, described by Kottelat in 1994. According to Seriously Fish it is known only from Krabi province in southern peninsular Thailand. Unusually for the genus, it occurs in neutral to alkaline, calcium-rich water and is a paternal mouthbrooder.
Taxonomy
- Family: Osphronemidae
- Genus: Betta
- Scientific name: Betta simplex
- Described: Kottelat, 1994
Habitat
According to Seriously Fish and Wikipedia, the species inhabits karstic limestone springs and wetlands near Krabi. The type locality features deep limestone sinkholes forming pools with a distinctive blue-green colour caused by a high proportion of dissolved calcium carbonate; fish congregate under overhanging vegetation.
Tank requirements
- Minimum tank volume: 40 L
- Temperature: 22-26 °C (72-79 °F)
- pH: 7.0-8.0
- GH: 10-25 °dGH
- Lifespan: 2-4 years
- Water flow: low; hard, alkaline water tolerated
Diet
Betta simplex is carnivorous, likely preying on aquatic and terrestrial invertebrates in nature. Seriously Fish reports captive fish accept dried foods but should receive small live or frozen foods such as Daphnia, Artemia or chironomid larvae regularly.
Compatibility
A mid-water species. Seriously Fish notes it is not among the more aggressive members of the genus and can be maintained in a pair or group, but it is not recommended for the standard community aquarium. Other male bettas and aggressive fish should be avoided.
Breeding
Betta simplex is a paternal mouthbrooder. According to Seriously Fish, the male incubates eggs for roughly 9 to 16 days; popular accounts cite an incubation of about 10 days before fry are released.
Conservation status
Wikipedia reports Betta simplex as Critically Endangered on the IUCN Red List, citing over-exploitation and degradation of its restricted habitat through pollution and surrounding land development.
Betta simplex Breeding Guide
Overview
Betta simplex, the Krabi mouthbrooder (family Osphronemidae), is a wild betta endemic to Krabi province in southern Thailand, with populations near Ao Luek associated with limestone springs. Seriously Fish gives a maximum standard length of 45-60 mm. It is a paternal mouthbrooder, in which the male incubates the eggs orally.
Sexing
Seriously Fish notes males are larger and display a greater extent of iridescent scaling on the head, a broader head shape and more extended fins than females.
Conditioning
Condition adults on small live and frozen foods. Seriously Fish lists 20-28 C, pH 7.0-8.0 and 54-215 ppm hardness, reflecting the hard, alkaline limestone-spring water of its origin; a single pair or a small group can be used for breeding.
Breeding Setup
A quiet, well-covered tank with hard, alkaline water and some cover suits the species. As a mouthbrooder, no bubble nest is built, so structure is for security rather than spawning substrate.
Spawning Behaviour & Trigger
Seriously Fish describes courtship leading to an embrace in which eggs and milt are released, with the male wrapped around the female. Fertilised eggs are caught on the male's anal fin, then the female picks them up and spits them into the water for the male to retrieve and hold orally, repeating until the female is spent of eggs.
Egg & Fry Care
Seriously Fish gives an incubation period of 9-16 days, after which the male releases free-swimming fry. Reports suggest the adults do not harm the young, which may develop faster when left with the parents. Fry are large enough to accept motile foods such as microworm and Artemia nauplii immediately, though excessive brine shrimp may cause problems; use small, regular water changes rather than large ones.
Common Challenges
Holding males may spit a brood prematurely if stressed or disturbed, so the tank should be kept quiet and stable. Hard, alkaline water and a calm environment give the best brooding success.