Betta hendra
Etymology
hendra: named for Hendra Tommy (Kurnia Aquarium, Palangkaraya, Kalimantan Tengah, Borneo), who discovered and first exported the species.
Classification
Order: Perciformes Family: Osphronemidae
Distribution
Palangkaraya is the capital city of Kalimantan Tengah (Central Kalimantan) province, Indonesian Borneo and B. hendra is known only from the Sabangau peat swamp forest, home to the world’s largest Orang Utan population and located to the immediate south and west of the city.
Type locality is given as ‘Indonesia, Borneo, Kalimantan Tengah, about 3 km south-east of Palangkaraya in direction of Berengbengkel; 02° 16.5 S, 113° 56.6 E’.
Habitat
The Sabangau peat swamp is drained by the Sungai Sabangau (River Sabangau) which is a typical black water system with thick marginal vegetation and dark brown water stained with humic substances and other chemicals released by decaying organic material.
The dissolved mineral content in such habitats is usually negligible, the pH can be as low as 3.0 or 4.0 and the substrate is normally littered with fallen leaves, branches and submerged tree roots.
At the type locality in May 2011 pH was around 4.0, conductivity 6 μS/cm and water temperature 28.5 °C.
The water was still, between 5 and 50 cm deep and shaded by riparian trees and bushes, and the fish were collected among aquatic and partially-submerged vegetation, sometimes alongside the congener B. foerschi (Schindler and Linke, 2013).
Maximum Standard Length
30 – 45 mm.
Aquarium SizeTop ↑
An aquarium with base measurements of 45 ∗ 30 cm or equivalent is large enough for a pair or small group.
Maintenance
Can be maintained in a fully-decorated aquarium although many breeders prefer not to use a substrate for ease of maintenance.
Driftwood roots and branches can be used and placed such a way that a few shady spots are formed while clay plant pots or lengths of piping can also be included to provide further shelter.
The addition of dried leaf litter further emphasises the natural feel and as well as offering additional cover for the fish brings with it the growth of microbe colonies as decomposition occurs.
These can provide a valuable secondary food source for fry and the tannins and other chemicals released by the decaying leaves are also considered beneficial for fishes from blackwater environments.
There is no need to use natural peat, however, the collection of which is both unsustainable and environmentally-destructive.
Like others in the genus this species seems to do best under fairly dim lighting.
You could add aquatic plant species that can survive under such conditions such as Microsorum, Taxiphyllum or Cryptocoryne spp., and a few patches of floating vegetation would be useful as well.
This species requires acidic conditions with negligible carbonate hardness and very low general hardness so a reverse osmosis unit or other method of obtaining soft water may need to be employed, and this can be further acidified using phosphoric acid or similar if necessary.
As it naturally inhabits sluggish waters filtration should not be too strong, with an air-powered sponge filter set to turn over gently adequate.
Keep the tank well-covered and do not fill it to the top as like all Betta spp. it requires occasional access to the layer of humid air that will form above the water surface, and is an excellent jumper.
Water Conditions
Temperature: 22 – 27 °C
pH: 4.0 – 6.5
Hardness: 18 – 90 ppm
Diet
Likely to feed mostly on insects and other small invertebrates in nature.
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, Artemia or bloodworm regularly to ensure development of optimal colour and condition.
Small insects such as newly-hatched crickets or Drosophila fruit flies are also suitable to use; it’s best to fill the stomachs of these by feeding them fish flakes or some kind of vegetable matter before offering them to the fish.
Take care not to overfeed as Betta spp. seem particularly prone to obesity.
Behaviour and CompatibilityTop ↑
Not recommended for the standard community set-up for reasons already touched upon.
It’s requirements and disposition mean it’s best kept alone or with very peaceful species since much bigger or more vigorous fishes are likely to intimidate and outcompete it.
Some small cyprinids and loaches that inhabit similar environments in nature are compatible, but be sure to research your choices before purchase.
It can be maintained in a pair or group and will display some interesting behavioural interactions under the latter circumstances.
Sexual Dimorphism
Adult males possess significantly more iridescent green pigmentation on the flanks and fins, plus the vertical bars on the operculum are darker and more intense than in females.
Reproduction
Bubble-nester. It’s particularly important to provide plenty of cover for the female, and empty camera film canisters or lengths of plastic tubing are often used to offer potential nesting sites.
Floating plants may be incorporated into the nest if present.
The tank should have the tightest-fitting cover you can find (some breeders use clingfilm instead, to ensure no gaps) because the fry need access to a layer of warm, humid air without which development of the labyrinth organ can be impaired.
The pair need not be separated prior to spawning.
The male may construct the nest in a tube or canister, under a broad plant leaf or among fine-leaved surface vegetation, and will not usually tolerate the female in the vicinity until it’s complete.
Just prior to spawning the body colour of the female pales and dark bars appear on the flanks, with the act itself normally occurring below the nest in an ‘embrace’ typical of osphronemids, with the male wrapping himself around the female.
At the point of climax milt and a few eggs are released which the female proceeds to catch between pelvic fins and body.
The male then transfers them to his nest while the female recovers any that fell.
This cycle is then repeated until the female is spent of eggs, a process that can take some time.
This is not a particularly prolific species with less than 20 eggs being typical although bigger broods of up to 50 are not uncommon.
Post-spawning the adults can normally be left in situ although the female is no longer actively involved with the male assuming sole responsibility for guarding and tending the nest.
The eggs hatch in 24-72 hours, remaining in the nest for a further few days until the yolk sac is fully-absorbed, while the male continues to collecting and return any that fall.
Once the fry begin to swim freely the male will lose interest, but the adults do not usually eat their offspring.
The fry are large enough to accept motile foods such as microworm and Artemia nauplii immediately, though it should be noted that there exist reports of young Betta developing health issues if fed excessive amounts of the latter.
Offer small amounts of different foods 2 -3 times per day for optimal growth rate, and don’t change too much water at once, with regular, small changes preferable to intermittent larger ones.
NotesTop ↑
This species has only been available to the aquarium hobby in limited numbers to date and is often referred to as B. sp. ‘Sengalang/Palangkayara’ although it’s also been traded as B. sp. ‘Sebangua’.
The former, rather long-winded name derives from the fact that it was initially marketed as two different species, i.e., B. sp. ‘Sengalang’ and B. sp. ‘Palangka’. The spelling of the latter was later corrected but the fish may still be seen labelled with either or both names.
Its colour pattern looks similar to that possessed by members of the B. foerschi group of closely-related species within the genus but its breeding strategy, adult size and behaviour preclude inclusion in that assemblage and it’s instead considered within the Betta coccina group of which members mostly comprise small, red-coloured fishes with the exceptions of B. hendra, B. persephone and B. miniopinna which are greenish or darkish.
Identifying some of the red ones correctly is not always easy as external patterning can be both similar and confusingly variable.
Members of the B. coccina group possess the following shared characters: small adult size (up to 40 mm SL); either red or black body colouration; presence of midlateral blotch in some species; 9 abdominal vertebrae (vs. 10-12 in all other Betta species); stenotypic inhabitants of forest peat swamps.
B. hendra can be told apart from other members of the group by the following combination of characters: flanks and unpaired fins with bright, iridescent green pigmentation; vertical opercular bars present; pelvic fin pointed with whitish tip; dorsal–fin rays 10-12; anal-fin rays 26-31; lateral scales 29-31; predorsdal scales 18-21.
The most closely-located member of the B. coccina group in terms of geography is B. uberis from which B. hendra can be distinguished by possession of 10-12 dorsal-fin rays (vs. 14-17 in B. uberis).
The genus Betta is the most speciose within the family Osphronemidae with almost 70 recognised members and looks set to grow further with new ones continuing to be described on a regular basis since the turn of the century.
Betta species have successfully adapted to inhabit a variety of ecological niches from stagnant ditches to flowing hill streams including some extreme environments such as highly acidic peat swamp forests.
The referral of members to a number of putative groups containing closely-related species is now generally accepted but largely based on morphological and behavioural characters meaning molecular phylogenetic work may prove useful in more precisely determining relationships between these fishes.
A full list of the species groups as currently recognised can be found here.
Like others in the suborder Anabantoidei this species possesses an accessory breathing organ known as the labyrinth.
So-called due to its maze-like structure this organ allows the fish to breathe atmospheric air to a certain extent.
Comprising paired suprabranchial organs formed via expansion of the epibranchial (upper) section of the first gill arch and housed in a chamber above the gills, it contains many highly-vascularised, folded flaps of skin which function as a large respiratory surface.
Its structure varies in complexity between species, tending to be better-developed in those inhabiting harsher environments.
References
- Schindler, I. and H. Linke, 2013 - Vertebrate Zoology 63(1): 35-40
Betta hendra – a new species of fighting fish (Teleostei: Osphronemidae) from Kalimantan Tengah (Borneo, Indonesia). - Tan, H. H. and P. K. L. Ng, 2005 - Raffles Bulletin of Zoology Supplement (13): 43-99
The fighting fishes (Teleostei: Osphronemidae: Genus Betta) of Singapore, Malaysia and Brunei. - Tan, H. H. and P. K. L. Ng, 2006 - Ichthyological Exploration of Freshwaters 17(2): 97-114
Six new species of fighting fish (Teleostei: Osphronemidae: Betta) from Borneo.
