''Betta balunga'' is a species of

gourami Gouramis, or gouramies , are a group of freshwater anabantiform fishes that comprise the family Osphronemidae. The fish are native to Asia—from the Indian Subcontinent to Southeast Asia and northeasterly towards Korea. The name "gourami", of ...

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 the island of

Borneo Borneo (; id, Kalimantan) is the third-largest island in the world and the largest in Asia. At the geographic centre of Maritime Southeast Asia, in relation to major Indonesian islands, it is located north of Java, west of Sulawesi, and eas ...

, and whose species name derives from the location where it was first described - the Balung River in

Sabah Sabah () is a States and federal territories of Malaysia, state of Malaysia located in northern Borneo, in the region of East Malaysia. Sabah borders the Malaysian state of Sarawak to the southwest and the North Kalimantan province of Indone ...

, eastern

Malaysia Malaysia ( ; ) is a country in Southeast Asia. The federation, federal constitutional monarchy consists of States and federal territories of Malaysia, thirteen states and three federal territories, separated by the South China Sea into two r ...

. It inhabits forest and blackwater streams, and grows to a length of .

Habitat and distribution

The type locality of ''Betta balunga'' corresponds to a locality in

Tawau Division Tawau Division ( ms, Bahagian Tawau) is one of the five administrative sub-divisions of Sabah, Malaysia. It occupies a total of 14,905 square kilometres or 20% of Sabah's territory. The main towns include the capital of Tawau, Lahad Datu, Kunak ...

, Sabah Province, Malaysian Borneo. Its distribution is currently considered to extend southwards from Tawau as far as the Sebuku and

Mahakam The Mahakam River ( Indonesian: ''Sungai Mahakam'') is third longest and volume discharge river in Borneo after Kapuas River and Barito River, it is located in Kalimantan, Indonesia. It flows from the district of Long Apari in the highlands ...

watersheds in

Kalimantan Timur East Kalimantan (Indonesian language, Indonesian: ) is a province of Indonesia. Its territory comprises the eastern portion of Borneo. It had a population of about 3.03 million at the 2010 census (within the current boundary), 3.42 million at th ...

(East Kalimantan) province in

Indonesia Indonesia, officially the Republic of Indonesia, is a country in Southeast Asia and Oceania between the Indian and Pacific oceans. It consists of over 17,000 islands, including Sumatra, Java, Sulawesi, and parts of Borneo and New Guine ...

. In Sebuku it has been collected alongside '' B. albimarginata'' from a flowing forest streams in very shallow (depth 5-10 cm) water among marginal plants roots and

leaf litter Plant litter (also leaf litter, tree litter, soil litter, litterfall or duff) is dead plant material (such as leaves, bark, needles, twigs, and cladodes) that have fallen to the ground. This detritus or dead organic material and its constituent ...

. In the Mahakam basin it typically inhabits sluggish, black water streams among submerged marginal vegetation and leaf litter. Specimens from the Mahakam differ from Tawau fish in some meristic counts but Tan and Ng (2005) considered them conspecific with ''B. balunga'' due to a lack of comparative material from the type locality.

Sexual dimorphism

Males have brighter colors, more iridescent scales on the head area, a broader head shape, and more extended fins than females.

Diet

In the wild

In the wild, ''Betta balunga'' has a diet that consists of insects such as ''

Drosophila ''Drosophila'' () is a genus of flies, belonging to the family Drosophilidae, whose members are often called "small fruit flies" or (less frequently) pomace flies, vinegar flies, or wine flies, a reference to the characteristic of many species ...

'' spp., zooplankton, and other small, aquatic invertebrates.

In the aquarium

The 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 ''

Daphnia ''Daphnia'' is a genus of small planktonic crustaceans, in length. ''Daphnia'' are members of the order Anomopoda, and are one of the several small aquatic crustaceans commonly called water fleas because their saltatory swimming style resembl ...

'', ''

Artemia ''Artemia'' is a genus of aquatic crustaceans also known as brine shrimp. It is the only genus in the family Artemiidae. The first historical record of the existence of ''Artemia'' dates back to the first half of the 10th century AD from Urmia La ...

'' or

bloodworm Blood worm or bloodworm is an ambiguous term and can refer to: * Larvae of a non-biting midge (family Chironomidae) containing hemoglobin * ''Glycera'' (annelid), a polychaete often used for fishing bait * Species of the Polychaeta subclass Scole ...

regularly to ensure development of optimal colour and condition.

Reproduction and development

''Betta balunga'' is a paternal

mouthbrooder Mouthbrooding, also known as oral incubation and buccal incubation, is the care given by some groups of animals to their offspring by holding them in the mouth of the parent for extended periods of time. Although mouthbrooding is performed by a va ...

, which means that the fry are incubated in the male's mouth. The female plays the more active role in initiating courtship and defending the area against intruders. After courting, eggs and milt are released during an "embrace" typical of

gouramis Gouramis, or gouramies , are a group of freshwater anabantiform fishes that comprise the family Osphronemidae. The fish are native to Asia—from the Indian Subcontinent to Southeast Asia and northeasterly towards Korea. The name "gourami", of ...

in which the male wraps his body around that of the female, and several "practice" embraces may be required beforehand. Once spawning begins, eggs are laid in small batches and picked up in the mouth of the female before being spat out into the water for the male to catch. Once the male has all the eggs in his mouth the cycle is repeated until the female is spent of eggs, a process which can take some time. The incubation period is 14 – 21 days at which point the male will begin to release fully-formed, free-swimming fry. The male might swallow or prematurely release the fry when stressed. The fry are large enough to eat motile foods such as

microworm The free-living nematode ''Panagrellus redivivus'' (sour paste nematode, or beer mat nematode from its occurrence in constantly moist felt beer mats), is known to many aquarium enthusiasts and fish keepers as the microworm. It is a tiny roundwor ...

and ''

nauplii Nauplius, Nauplia or Nauplios , may refer to : Greece-related * Nauplius (mythology), in Greek mythology, the son of Poseidon and Amymone, the father of Palamedes, and also the name of an Argonaut * Nauplia Nafplio ( ell, Ναύπλιο) is a ...

immediately.

References

balunga Fish of Asia Taxa named by Albert William Herre Fish described in 1940 {{Anabantiformes-stub