Beta (Fighter fish)

Classification:
                            

Kingdom:	Animalia
Phylum:	Chordata
Class:	Osteichthyes
Subclass:	Actinopterygii
Superorder:	Acanthopterygii
Order:	Perciformes
Family:	Osphronemidae
Subfamily:	Macropodusinae
Genus:	Betta
Species:	B. splendens

Picture:
                 female fighter fish

About:
The Siamese fighting fish, also sometimes colloquially known as the betta (Betta splendens), is a species in the gouramifamily which is popular as an aquarium fish. This species is native to the Mekong basin of Thailand, Laos, Cambodia, andVietnam, where it can be found in standing waters of canals, rice paddies, and floodplains.^[1] They are called pla-kad (biting fish) in Thai or trey krem in Khmer. They tend to be rather aggressive. In January 2014 a large population of the fish was discovered in the Adelaide River Floodplain in the Northern Territory, Australia.^[2] As an invasive species they pose a threat to native fish, frogs and other wildlife in the wetlands.
Reproduction:
                        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.^[4] 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.
Size:
        B. splendens usually grows to a length of about 6.5 cm (2.6 in).^[1] Although aquarium specimens are known for their brilliant colors and large, flowing fins, the natural coloration of B. splendens is a dull green, browns, and gray, and the fins of wild specimens are relatively short.

In the aquarium

Betta species prefer a water of around 23ºC-27ºC but have been seen to survive at the extremes of 20ºC-30ºC though their life quality may be diminished at these extremes of the betta's tolerance.^{[citation needed]} They have an organ known as the labyrinth organ which allows them to breathe air at the water's surface. This organ was thought to allow the fish to be kept in unmaintained aquaria,^[7] but this is a misconception, as poor water quality makes all tropical fish, including Betta splendens, more susceptible to diseases such as fin rot.

Properly kept and fed a correct diet, Siamese fighting fish live about two to four years in captivity, and up to 10 years in rare cases.

Varieties

B. splendens can be hybridized with B. imbellis, B. mahachaiensis, and B. smaragdina, though with the latter, the fry tend to have low survival rates. In addition to these hybrids within the Betta genus, intergeneric hybridizing of Betta splendens and Macropodus opercularis, the paradise fish, has been reported. A fairly recent variety to hit the markets is the king betta, a variety of largely unknown provenance which may or may not be derived from crossing B. splendens with B. raja.^[8]

Breeders around the world continue to develop new varieties. Often, the males of the species are sold preferentially in stores because of their beauty, compared to the females. Recently, breeders have developed in females the same range of colors previously only bred in males.^{[citation needed]} Females almost never develop fins as showy as males of the same type and are often more subdued in coloration, though some breeders manage to get females with fairly long fins and bright colors. .

Colors

A dalmatian orange male

Wild fish exhibit strong colors only when agitated.^{[citation needed]} Breeders have been able to make this coloration permanent, and a wide variety of hues breed true. Colors available to the aquarist include red, orange, yellow, blue, steel blue, turquoise/green, black, pastel, white ("opaque" white, not to be confused with albino), and multi-colored fish. The shades of blue, turquoise, and green are slightly iridescent, and can appear to change color with different lighting conditions or viewing angles; this is because these colors (unlike black or red) are not due to pigments, but created through refraction within a layer of translucent guanine crystals. Breeders have also developed different color patterns such as marble and butterfly, as well as metallic shades through hybridization^[9] like copper, gold, or platinum (these were obtained by crossing B. splendensto other Betta species).

Purple and blue female

A true albino betta has been feverishly sought since one recorded appearance in 1927, and another in 1953 .^{[citation needed]}Neither of these was able to establish a line of true albinos. In 1994, a hobbyist named Kenjiro Tanaka claimed to have successfully bred albino bettas.^[10]

Some bettas will change colors throughout their lifetime (known as marbling), attributed to a transposon.^[11]

Finnage variations

A metallic, double-tail male

A crowntail male

Breeders have developed several different finnage and scale variations:

• Veil tail (extended finnage length and non-symmetrical tail; caudal fin rays usually only split once) the most common tail type seen in pet stores.
• Crown tail (fin rays are extended well beyond the membrane and consequently the tail can take on the appearance of a crown; also called fringetail)
• Comb tail (less extended version of the crown tail, derived from breeding crown and another finnage type)
• Half-moon ("D" shaped caudal fin that forms a 180° angle, the edges of the tail are crisp and straight)
• Over-half-moon (caudal fin is in excess of the 180° angle, byproduct of trying to breed half-moons, can sometimes cause problems because the fins are too big for the fish to swim properly)
• Rose tail (halfmoon variation with so much finnage that it overlaps and looks like a rose)
• Feather tail (similar to the rose tail, with a rougher appearance)
• Short-finned fighting style (sometimes called "plakat")
• Half-moon plakat (short-finned half-moon, plakat and half-moon cross)
• Double tail (the tail fin is duplicated into two lobes and the dorsal fin is significantly elongated, the two tails can show different levels of bifurcation depending on the individual)
• Delta tail (tail spread less than that of a half-moon with sharp edges)
• Half-sun (combtail with caudal fin going 180°, like a half-moon)
• Elephant ear (pectoral fins are white, and much larger than normal, resembling the ears of an elephant)
• Spade tail (caudal fin has a wide base that narrows to a small point)

Behavior

A male attacking and flaring at his reflection in a mirror.

Males and females flare or puff out their gill covers (opercula) to appear more impressive, either to intimidate other rivals or as an act of courtship. Other reasons for flaring is when they are startled by movement or change of scene in their environments. Both sexes display horizontal bars (unless they are too light a color for this to show) if stressed or frightened; however, such a color change, common in females of any age, is very rare in mature males. Females often flare at other females, especially when setting up a pecking order. Flirting fish behave similarly, with vertical instead of horizontal stripes indicating a willingness and readiness to breed (females only). In fact, the fish flare their fins and gill covers as a sign of aggression or flirting with other fish. Bettas sometimes require a place to hide, even in the absence of threats. They may set up a territory centered on a plant or rocky alcove, sometimes becoming highly possessive of it and aggressive toward trespassing rivals.

The aggression of this fish has been studied by ethologists and comparative psychologists.^[12] These fish have historically been the objects of gambling; two male fish are pitted against each other in a fight and bets are placed on which one will win. One fish is almost always killed as a result. To avoid this, male Siamese fighting fish are best isolated from one another. Males will occasionally even respond aggressively to their own reflections in a mirror. Though this is obviously safer than exposing the fish to another male, prolonged sight of their reflection can lead to stress in some individuals. Not all Siamese fighting fish respond negatively to other male fish, especially if not too many of them are present.^{[citation needed]}

Several females in a community tank with mollies and rainbowfish

Name

Although commonly called a betta in the aquarium trade, especially in North America, that is the name of a genus not only containing this fish, but also other species. B. splendens is more accurately called by its scientific name or "Siamese fighting fish", to avoid confusion with the other species in the genus.