Siamese Fighting Fish

Betta splendens (commonly known as the Siamese Fighting Fish or Betta).

This species’ common name is derived from the tradition of keeping the fish in order to fight against each other in organised «bouts» upon which participants and onlookers place wagers. It has been extensively line-bred for vigour, strength, and the ornamental trade, and hybridised with the congeners Betta imbellis, Betta smaragdina, and Betta mahachaiensis.

Occurs naturally throughout central Thailand, from Chiang Rai province in the north to Surat Thani and Phang Nga provinces at the northern extremity of the Malay Peninsula, just below the Isthmus of Kra. Records from the remainder of southern (peninsular) Thailand, and the Mekong River basin in eastern Thailand, Laos, Vietnam, and Cambodia refer to other species or introduced populations.

The type locality is «Menam River, Thailand», which refers to the Chao Phraya river basin.

Inhabits still and sluggish waters, including rice paddies, swamps, roadside ditches, streams, and ponds. These are often shaded by submerged, surface, or marginal vegetation and sometimes contain little dissolved oxygen. Water conditions tend to vary and change rapidly during the annual monsoon season. Substrates can vary from leaf litter to mud, sand, or deep sediment.

Chao Phraya River

This species fares best in a well-planted, shady aquarium with plenty of surface cover in the form of tall stem plants, floating types such as Salvinia or Riccia spp., or tropical lilies from the genus Nymphaea. Cryptocoryne spp. are also a good choice.

Driftwood can also be used and other plants such as Microsorum or Taxiphyllum spp. maybe attached to it. Small clay plant pots, lengths of plastic piping, or empty camera film cases 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.

As it naturally inhabits sluggish environments strong water movement should be avoided, with an air-powered sponge filter set to turn over gently adequate. Keep the aquarium well-covered and do not fill it to the top since like all Betta splendens it requires occasional access to the layer of humid air that will form above the water surface and is an excellent jumper.

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 the development of optimal colour and condition. Small insects such as pinhead crickets or Drosophila fruit flies are also suitable to use; it is best to fill the stomachs of these by feeding them fish flakes or some kind of vegetable matter before offering them to the fish.

Not recommended for the standard community aquarium. Its care requirements and disposition mean it is best kept alone. Sometimes individual fish may tolerate other species, but this is the exception, not the expected norm.

Some small cyprinids and loaches that inhabit similar environments in nature are suitable, but proper research prior to purchase is essential and in most cases, it is best maintained alone. Species with body shapes or trailing finnage should certainly be avoided, since a male may view these as rivals.

Like others in the suborder Anabantoidei, this species possesses an accessory breathing organ known as the labyrinth, which permits 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 that function as a large respiratory surface. Its structure varies in complexity between species, tending to be more developed in those inhabiting harsher environments.