Betta: from ikan betah, the vernacular Malay for species of this genus.
foerschi: named for Dr. Walter Foersch who co-collected the type series.
Known from a handful of localities in Kalimantan Tengah (Central Kalimantan) province, and around the settlement of Kubu in Kalimantan Barat (Western Kalimantan) provinces, Indonesian Borneo.
Type locality is ‘Mentaya River system, 250 kilometers northwest of Bandjarmasin, Borneo, Indonesia’.
Typically inhabits forest swamp streams and pools, some of which have been measured at just a few centimetres deep. These are usually shaded from the sun, the dense canopy of branches above meaning very little light penetrates the water surface.
Marginal vegetation also tends to grow thickly. The water itself is often stained with humic acids and other chemicals released by decaying organic material. The dissolved mineral content is negligible, pH low, and substrate composed mainly of fallen leaves, branches, and submerged tree roots.
Maximum Standard Length
40 – 50 mm.
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 offers additional cover and brings with it the growth of microbe colonies as decomposition occurs. These can provide a valuable secondary food source for fry, while tannins and other chemicals released by the decaying leaves are 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. Aquatic plant species that can survive under such conditions include Microsorum, Taxiphyllum or Cryptocoryne spp., while floating vegetation is also appreciated by the fish.
This species requires acidic conditions with negligible carbonate hardness and very low general hardness, meaning a reverse osmosis unit or other method of obtaining soft water may need to be employed. 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.
Temperature: 22 – 28 °C
pH: 4.0 – 6.0
Hardness: 18 – 90 ppm
Likely to prey on aquatic and terrestrial invertebrates in nature.
Captive fish will normally accept dried products once they are recognised as edible, but should be offered plenty of small live or frozen foods such as Daphnia, Artemia or chironomid larvae (bloodworm) regularly to ensure development of optimal colour and condition.
Take care not to overfeed as Betta spp. seem particularly prone to obesity.
Males are more colourful than females, and develop extended unpaired fins. The opercular bars are usually orange-red and more well-defined in males, golden-yellow in females.