The
Siamese fighting fish, also sometimes colloquially known as the betta (Betta
splendens), is a species in the gourami family which is popular as an aquarium
fish. They are called pla-kad (biting fish) in Thai or trey krem in Khmer. They
tend to be rather aggressive.
This
species is native to the Mekong basin of Laos, Cambodia, Vietnam and Thailand,
the latter formerly known as Siam. The fish can be found in standing waters of
canals, rice paddies and floodplains.
In January
2014 a large population of the fish was discovered in the Adelaide River
Floodplain in the Northern Territory, Australia. As an invasive species they
pose a threat to native fish, frogs and other wildlife in the wetlands.
Diet
Betta splendens feeds on zooplankton, crustaceans, and the
larvae of mosquitoes and other water-bound insects.
Reproduction and early development
Male bettas flare their gills, twist their bodies, and
spread their fins if interested in a female. The female darkens in colour, then
curves her body back and forth as a response. Males build bubble nests of
various sizes and thicknesses at the surface of the water. They do this
regularly even if there is no female present.
Plants or rocks that break the surface often form a base for
bubble nests. The act of spawning itself is called a "nuptial
embrace", for the male wraps his body around the female; around 10–40 eggs
are released during each embrace, until the female is exhausted of eggs. The
male, in his turn, releases milt into the water, and fertilization takes place
externally. During and after spawning, the male uses his mouth to retrieve
sinking eggs and deposit them in the bubble nest (during mating the female
sometimes assists her partner, but more often she simply devours all the eggs
she manages to catch). Once the female has released all of her eggs, she is chased
away from the male's territory, as she will likely eat the eggs. The eggs
remain in the male's care. He carefully keeps them in his bubble nest, making
sure none falls to the bottom, repairing the bubble nest as needed. Incubation
lasts for 24–36 hours; newly hatched larvae remain in the nest for the next two
to three days until their yolk sacs are fully absorbed. Afterwards, the fry
leave the nest and the free-swimming stage begins. In this first period of
their lives, B. splendens fry are totally dependent on their gills; the
labyrinth organ which allows the species to breathe atmospheric oxygen
typically develops at three to six weeks of age, depending on the general
growth rate, which can be highly variable. B. splendens can reach sexual
maturity at an age as early as 4–5 months.
History
Some people of Thailand and Malaysia are known to have
collected these fish prior to the 19th century from the wild.
In the wild, bettas spar for only a few minutes or before
one fish backs off. Bred specifically for fighting, domesticated betta matches
can go on for much longer, with winners determined by a willingness to continue
fighting. Once one fish retreats, the match is over.
Seeing the popularity of these fights, the king of Thailand
started licensing and collecting these fighting fish. In 1840, he gave some of
his prized fish to a man who, in turn, gave them to Dr. Theodor Cantor, a
medical scientist. Nine years later, Dr. Cantor wrote an article describing
them under the name Macropodus pugnax. In 1909, the ichthyologist Charles Tate
Regan, realizing a species was already named Macropodus pugnax, renamed the
domesticated Siamese fighting fish Betta splendens.
1892 this species was imported to France by the French
aquarium fish importer Pierre Carbonnier in Paris, and 1896 the German aquarium
fish importer Paul Matte in Berlin, imported the first specimens to Germany
from Moscow.
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