The Krabi mouth-brooding betta, ''Betta simplex'', is a

species In biology, a species is the basic unit of classification and a taxonomic rank of an organism, as well as a unit of biodiversity. A species is often defined as the largest group of organisms in which any two individuals of the appropriate s ...

of gourami

endemic Endemism is the state of a species being found in a single defined geographic location, such as an island, state, nation, country or other defined zone; organisms that are indigenous to a place are not endemic to it if they are also found elsew ...

to Krabi Province,

Thailand Thailand ( ), historically known as Siam () and officially the Kingdom of Thailand, is a country in Southeast Asia, located at the centre of the Indochinese Peninsula, spanning , with a population of almost 70 million. The country is bo ...

. It inhabits

karst Karst is a topography formed from the dissolution of soluble rocks such as limestone, dolomite, and gypsum. It is characterized by underground drainage systems with sinkholes and caves. It has also been documented for more weathering-resistant ro ...

springs and

wetlands A wetland is a distinct ecosystem that is flooded or saturated by water, either permanently (for years or decades) or seasonally (for weeks or months). Flooding results in oxygen-free (anoxic) processes prevailing, especially in the soils. The ...

, where it lives amongst vegetation close to the banks. This species can reach a length of . This species can also be found in the

aquarium An aquarium (plural: ''aquariums'' or ''aquaria'') is a vivarium of any size having at least one transparent side in which aquatic plants or animals are kept and displayed. Fishkeepers use aquaria to keep fish, invertebrates, amphibians, aq ...

trade and is taken from the wild for this purpose. The

International Union for Conservation of Nature The International Union for Conservation of Nature (IUCN; officially International Union for Conservation of Nature and Natural Resources) is an international organization working in the field of nature conservation and sustainable use of natu ...

has assessed it as being " critically endangered" due to over-exploitation and the degradation of its restricted habitat by pollution and development of the surrounding land for farming.

Description

The Krabi mouth-brooding betta is an oblong fish with rounded fins, growing to a length of about . The basic colour is yellowish-brown or greyish-brown with three faint longitudinal stripes. The gill-cover has a bluish-green patch and the fins have a blue iridescence. The pelvic fins are short and the anal fin long, with a dark margin. The caudal-fin is rounded and undivided.

Distribution and habitat

This species is known from a single location in Krabi Province, Thailand, where its total area of occupation is less than . It lives in a limestone area where water flows from

aquifer An aquifer is an underground layer of water-bearing, permeable rock, rock fractures, or unconsolidated materials (gravel, sand, or silt). Groundwater from aquifers can be extracted using a water well. Aquifers vary greatly in their characterist ...

s through the karst limestone to form pools and streams of clear, neutral to alkaline water. The fish usually congregate under overhanging vegetation in the streams and ditches.

Ecology

Bettas are known as anabantids because they have a special lung-like

labyrinth In Greek mythology, the Labyrinth (, ) was an elaborate, confusing structure designed and built by the legendary artificer Daedalus for King Minos of Crete at Knossos. Its function was to hold the Minotaur, the monster eventually killed by the ...

ine organ in its head which enables them to obtain oxygen direct from the air. For this reason, they can live in water with very little dissolved oxygen, and can survive out of water for a short time as long as they remain damp. They are also efficient jumpers. The Krabi mouth-brooding betta probably feeds on insects, crustaceans, other small invertebrates and zooplankton. This fish is a paternal mouth brooder; the male fish takes the fertilised eggs into his mouth and keeps them there until they hatch.

Status

''B. simplex'' has a very small total area of occurrence which puts it at risk from habitat destruction by run-off of chemicals from agricultural land and by tourism. This species is also threatened by over-exploitation, with fish being collected for the aquarium trade and used locally as bait when fishing for

eel Eels are ray-finned fish belonging to the order Anguilliformes (), which consists of eight suborders, 19 families, 111 genera, and about 800 species. Eels undergo considerable development from the early larval stage to the eventual adult stage ...

s. For these reasons, the

has assessed the conservation status of this fish as being " critically endangered".

References

{{Taxonbar, from=Q1090768 Fish of Thailand Krabi mouth-brooding betta Taxa named by Maurice Kottelat Fish described in 1994 Endemic fauna of Thailand Taxonomy articles created by Polbot