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Betta brownorum WITTE & SCHMIDT, 1992

Etymology

brownorum: named for Barbara and Allan Brown, who first collected this species.

Classification

Osphronemidae

Distribution

Endemic to the island of Borneo where it’s restricted to southern and western parts of the state of Sarawak, Malaysia with a handful of populations across the border in Kalimantan Barat (West Kalimantan) province, Indonesia.

Type locality is ‘Small peat swamp forest, 2.55 kilometers south of Batang Rejang ferry on road from Sibu to Kuching, Sarawak, East Malaysia, 2°08’N, 112°00’30″E’.

According to Tan and Ng (2005) its range in Sarawak extends from Sibu southwest to Kuching and onwards as far as Matang.

It’s been collected at several different localities and these populations are often labelled by collectors and enthusiasts to maintain accuracy and preserve pure bloodlines, e.g., Sibu, Matang.

Apparently the greenish lateral blotch varies in size according to collection locality, with specimens from Matang exhibiting a much larger spot than those collected around Sibu.

Many habitats around the former have disappeared as much of the zone has been turned over to housing projects.

Habitat

A stenotypic inhabitant of peat swamp forests and associated black water streams.

The dense canopy of branches above means very little light penetrates the surface of such environments, and riparian vegetation also tends to grow thickly.

The water is typically stained darkly with humic acids and other chemicals released by decaying organic material.

The dissolved mineral content is generally negligible and pH can be as low as 3.0 or 4.0.

The substrate is usually covered by fallen leaves, branches and submerged tree roots and at certain times of year the fish may be forced to survive within the moist leaf litter for several weeks as permanent water is not always available.

At the type locality the forest floor was covered with approximately 10 cm of undecomposed leaf litter with a system of 5-10 cm deep puddles.

Aquatic vegetation included Cryptocoryne pallidinervia and Barcleya cf. motleyi and during periods of rainfall the entire forest floor was flooded and remained that way for a period.

Other fishes present included ‘Puntiuspentazona, Rasbora kalochroma, Clarias teijsmanni and Monopterus albus plus the congener Betta climacura.

Maximum Standard Length

25 – 30 mm.

Aquarium SizeTop ↑

An  aquarium with base measurements of 45 ∗ 30 cm could house 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

Temperature24 – 30 °C

pH3.0 – 6.0

Hardness18 – 90 ppm

Diet

Preys on insects and other small invertebrates in nature with the stomachs of four dissected wild specimens containing arthropods including terrestrial ants and aquatic mites (Witte and Schmidt, 1992).

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 DaphniaArtemia or bloodworm regularly to ensure development of optimum colour and condition.

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 care requirements and disposition mean it is 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 suitable, but proper research prior to purchase is essential.

Mixed reports exist as to whether it can be maintained in multiple pairs or harem-type groups comprising a single male alongside several females.

Some observe that although some chasing and squabbling over territory occurs actual physical damage is rare, while others recommend keeping it in single pairs having observed sustained aggression towards conspecifics from the dominant individuals in a group.

Sexual Dimorphism

Males are more colourful and develop longer fins than females as they mature.

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 24-48 hours, remaining in the nest for a further 3-4 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 is included in the B. coccina group of closely-related species within the genus.

This assemblage mostly comprises small, red-coloured fishes with the exceptions of B. hendraB. persephone and B. miniopinna which are greenish or darkish, and identifying some of them can be problematic 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. brownorum can be told apart from other members of the group by the following combination of characters: large iridescent green lateral blotch in both male and female; reddish-magenta body colour; no parallel vertical iridescent bars on opercle; pelvic fin falcate, with white filamentous tip, rest red; median fins without iridescent green spots; dorsal-fin rays 10-11; anal-fin rays 26-28; subdorsal scales 6-7; lateral scales 29½-31; predorsdal scales 18-20.

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.

Member 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 groups containing closely-related species is now generally accepted but largely based on morphological and behavioural characters.

Molecular phylogenetic work may therefore 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

  1. Witte, K.-E. and J. Schmidt, 1992 - Ichthyological Exploration of Freshwaters 2(4): 305-330
    Betta brownorum, a new species of anabantoids (Teleostei: Belontiidae) from northwestern Borneo, with a key to the genus.
  2. Tan, H. H. and P. K. L. Ng, 2005 - Raffles Bulletin of Zoology Supplement 13: 115-138
    The labyrinth fishes (Teleostei: Anabantoidei, Channoidei) of Sumatra, Indonesia.
  3. 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.

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