In the cruel pet trade, betta fish (aka Siamese fighting fish) are fighting for their lives. Pet shops, discount superstores, florists, and even websites sell bettas who are forced to live in minuscule cups, small bowls, and even flower vases. Many people who buy these fish on a whim dont know enoughif anythingabout proper betta care, which is more complex and expensive than they realize. On this page, learn why you should never buy bettas (or any other animal) from a pet store. If you already have a betta fish companion, well show you how to give that animal the best possible life.
While some bettas are captured in the wild, the vast majority of those sold in the U.S. come from breeding farms in Thailand and other countries in Southeast Asia, where its common practice to keep them in small bottles. When its time to pack them for transport to the U.S., fish are haphazardly dumped into baskets covered with nets and scooped up into small plastic cups.
A diet consisting solely of plant roots may keep them alive for a while, but since it lacks the proper nutrients for this species, the fish eventually become sick and die. Too much uneaten food and waste material in aquarium tanks can overload them, causing ammonia and nitrite levels to become toxic. If aggression becomes an issue in any community tank, you should keep and maintain a separate, working quarantine aquarium in which individuals can be placed to avoid conflict with other fish.
Pet shops, discount superstores, florists, and even online catalogs sell decorative bettas in small cups or flower vases. Remember: Purchasing a betta fish from a pet store or breeder isnt rescuing an animalits funding the continued abuse and exploitation of that species.
Where are betta fish found in the wild?
While some bettas are captured in the wild, the vast majority of those sold in the U.S. come from breeding farms in Thailand and other countries in Southeast Asia, where it’s common practice to keep them in small bottles.
Where did betta fish originally come from?
These bettas originate from the Mekong and Chao Phraya river basins in Thailand (formerly called Siam). The fish hang out in shallow, nearly stagnant waters, such as marshes, flood plains and rice paddies.
Are betta fish from Japan?
They are not native to Japan or China. Betta fish are sometimes called Japanese fighting fish or Chinese fighting fish although they are not native to either country.
Do betta fish get lonely?
Do They Get Lonely? Betta fish are naturally territorial and should not be housed with any other betta fish because they will fight and injure each other, often resulting in death. They are unlikely to get lonely in their tank ; however, if they are in a small tank, they may get bored.
The Siamese fighting fish, better known as Betta splendens or just Betta, is one of the most popular aquarium fish worldwide. Loved by aquarists for its splendid colors, flowing fins and feisty attitude, its almost impossible to imagine the aquarium hobby without it. Despite this, many aquarists have little idea of the origins of their finned friend.
For example, very recently (July 2019), thousands of rogue Betta splendens were found in the Adelaide River and floodplains of Darwin, Australia. Betta fish in the wild are typically found in shallow bodies of water stuffed with vegetation, such as rice paddies and swamps.
Dont let the darkness of the water fool you: its tea colored due to natural tannins released by fallen organic material, not dirty. Wild Bettas that are captured and raised in captivity can be trained to accept other types of foods as well, such as flakes and pellets. As it was mentioned earlier, its commonly believed that Betta fish originate from Thailand, where wild males were first caught and bred for fighting.
He was bred by a Frenchman named Guy Delaval in the early 1980s, and was shared between multiple breeders to solidify the halfmoon tail type as we know it today.
Betta fish, also called Siamese or Japanese fighting fish, are beautiful to look at, fun to watch, and dont require much space at all. Most bettas sold in pet stores can be kept in small fish bowls, sometimes with plants and even other fish (depending on the species). Keep reading to learn all about betta fish, plus some fun betta trivia.
Betta fish are native to the rice paddies, canals, floodplains and drainage ditches of Southeast Asia, most notably Thailand, Vietnam, Malaysia, Laos and Cambodia. While betta fish call Southeast Asia home, they are an invasive species and have been found in rivers and lake systems around the world.
The Siamese fighting fish (Betta splendens), commonly known as the betta, is a freshwater fish native to Southeast Asia, namely Cambodia, Laos, Myanmar, Malaysia, Indonesia, Thailand, and Vietnam. While there are 73 species of the genus Betta, only Betta splendens are eponymously called “bettas”, due largely to their global popularity as pets: they are among the most widely available aquarium fish in the world, due to their varied and vibrant colour, diverse morphology, and relatively low maintenance.
Bettas are well known for being highly territorial, with males prone to attacking each other if housed in the same tank; without a means of escape, this will usually result in the death of one or both fish.  Bettas are exceptionally tolerant of low oxygen levels and poor water quality, owing to their special labyrinth organ , a characteristic unique to the suborder Anabantoidei that allows for the intake of surface air.
In addition to its worldwide popularity, the Siamese fighting fish is the national aquatic animal of Thailand,  which remains the primary breeder and exporter of bettas for the global aquarium market. Despite their abundance as pets, B. splendens is listed as ” vulnerable ” by the IUCN , due to increasing pollution and habitat destruction . Betta splendens is more accurately called by its scientific name or “Siamese fighting fish” to avoid confusion with the other members of the genus.
This name is used in Thailand for all members of the Betta genus, which share similar aggressive tendencies, rather than for any specific strain of the Siamese fighting fish. In captivity, Siamese fighting fish have been selectively bred to display a vibrant array of colours and tail types. According to Witte and Schmidt (1992), Betta splendens is native to Southeast Asia, including the northern Malay Peninsula , central and eastern Thailand , Kampuchea ( Cambodia ), and southern Vietnam .
Similarly, a report from Froese and Pauly (2019) identifies Betta splendens as native to Cambodia, Laos , Thailand, and Vietnam. Wherever they are found, Betta splendens generally inhabit shallow bodies of water with abundant vegetation, including marshes , floodplains , and paddy fields . The historic prevalence of rice farming across Southeast Asia, which provided an ideal habitat for bettas, led to their discovery and subsequent domestication by humans.
 The combination of shallow water and high air temperature causes gases to rapidly evaporate, leading to a significant deficit of oxygen in the betta‘s natural habitat.  This environment likely led to the evolution of the lung-like labyrinth organ , which allows Siamese fighting fishlike all members of the suborder Anabantoidei to breathe directly from the air. Subsequently, bettas can live and even thrive in harsher environments than other freshwater fish, which in turn leaves them with fewer natural predators and competitors.
The tropical climate of the betta‘s natural habitat is characterised by sudden and extreme fluctuations in water availability, chemistry, and temperature.  Consequently, Siamese fighting fish are highly adaptable and durable, able to tolerate a variety of harsh or toxic environments; this accounts for their popularity as pets, as well as their ability to successfully colonise bodies of water all over the world. In January 2014, a large population of bettas was discovered in the Adelaide River Floodplain in the Northern Territory, Australia .
The primary threats are habitat destruction and pollution, caused by urban and agricultural development across central Thailand. Bettas can be fed a varied diet of pellets, flakes, or frozen foods like brine shrimp , bloodworms , daphnia and many others. Due to their short digestive tractsa characteristic of most carnivores bettas have difficulty processing carbohydrates such as corn and wheat, which are commonly used as fillers in many commercial fish foods.
Bettas are susceptible to overfeeding, which can lead to obesity, constipation, swim bladder disease, and other health problems; excessive food may also pollute the water.  Bettas can go up to two weeks without eating, and it is not uncommon for them to have no appetite for one or two days, especially following stressful episodes such as a water change or being introduced into a new tank. If interested in a female, male bettas will flare their gills, spread their fins and twist their bodies in a dance-like performance.
Incubation lasts for 2436 hours; newly hatched larvae remain in the nest for the next two to three days until their yolk sacs are fully absorbed. Some people in Malaysia and Thailand are known to have collected wild bettas at least by the 19th century, observing their aggressive nature and pitting them against each other in gambling matches akin to cockfights . In 1840, he gave some of his prized fish to Danish physician Theodore Edward Cantor , who worked in the Bengal medical service.
In 1909, British ichthyologistCharles Tate Regan found there was a related species already named Macropodus pugnax , and thus renamed the domesticated Siamese fighting fish, Betta splendens, or “splendid fighter”. Betta splendens first entered the Western aquarium trade in the late 19th century; the earliest known arrival is 1874 in France, when French aquaria expert and ichthyologist Pierre Carbonnier began importing and breeding several specimens. In 1896, German tropical fish expert Paul Matte brought the first specimens into Germany from Moscow, most likely from the strain developed by Carbonnier.
Fighting fish were also present in Australia by 1904, based on an article written by British-born zoologist Edgar Ravenswood Waite and published by the Australian Museum in Sydney.  In 1927, an article was published in Germany describing the long, flowing fins of the “veiltail” breed, which indicates an emphasis on aesthetic beauty. The IBC aimed to breed varieties that would be healthier and more symmetrical in fins and body shape, with an emphasis on animal welfare .
 Due to their labyrinth organ , bettas can endure low oxygen levels, but cannot survive for long in unmaintained aquaria, as poor water quality makes all tropical fish more susceptible to diseases like fin rot .  Similarly, live aquatic plants provide a supplemental source of filtration, in addition to crucial enrichment to the betta.  Although some betta enthusiasts claim there is a minimum tank size, determining a strict baseline is somewhat arbitrary and subject to debate.
Although males bettas are solitary and aggressive towards one another, they can generally cohabit with many types of fish and invertebrates if there is adequate space and hiding places.  Species that shoal , such as tetras and danios , are considered most ideal, since they usually keep to themselves and can endure the territorial nature of bettas with their numbers. It is not recommended to keep male and female bettas together, except temporarily for breeding purposes, which should always be undertaken with caution and supervision.
Bettas are fairly intelligent and inquisitive, and thus require stimulation; otherwise they can become bored and depressed, leading to lethargy and a weaker immune system.  Decorations such as plastic or live plants, rocks, caves, driftwood, and other ornaments provide crucial enrichmentprovided they do not have rough textures or jagged edges, which can damage the delicate fins. In the wild, Siamese fighting fish spend most of their time concealing themselves under floating debris or overhanging plants to avoid potential predators.
 Floating plants and leaves can help bettas feel more secure, while also giving males an anchor from which to build their bubble nests.  Abundant vegetation of any kind is generally recommended to provide maximum security and to cater to the betta‘s instinct to claim protective territory. Indian almond leaves are increasingly popular for providing something closer to the natural foliage under which bettas would hide in the wild.
Their tannins allegedly confer several health benefits,  including treating certain ailments like fin rot and bladder disease, and stabilising the pH of the water.  A larger tank with proper filtration, regular maintenance, and an abundance of decor and hiding spaces, along with a rich, protein-based diet, increases the likelihood of a long lifespan. Like all tropical fish in captivity, bettas are susceptible to several kinds of diseases, usually caused by bacterial, fungal, or parasitic infections.
Betta splendens can be hybridised with B. imbellis , B. mahachaiensis , and B. smaragdina , though with the latter, the fry tend to have low survival rates. Breeders have also developed different colour patterns such as marble and butterfly, as well as metallic shades like copper, gold, or platinum, which were obtained by crossing B. splendens to other Betta species). Flirting fish behave similarly, with vertical instead of horizontal stripes indicating a willingness and readiness to breed.
They may set up a territory centered on a plant or rocky alcove, sometimes becoming highly possessive of it and aggressive toward trespassing rivals; consequently, bettas, if housed with other fish, require at least 45 litres (about 10 gallons). Betta aggression has historically made them objects of gambling; two male fish are pitted against each other to fight, with bets placed on which one will win. In general, studies have shown that females exhibit similar aggressive behaviours to males, albeit less frequently and intensely.
 An observational study examined a group of female Siamese fighting fish over a period of two weeks, during which time they were recorded attacking, flaring, and biting food.  The results of this research suggest that female Siamese fighting fish warrant as much scientific study as males, as they seem to have variations in their behaviours as well. Similarly, researchers have found that when pairs of male Siamese fighting fish were kept together in the same tank for a three-day period, aggressive behaviour was most prevalent during the mornings of the first two days of their cohabitation.
 In regards to oxygen consumption, one study found that when two male bettas fought, the metabolic rates of both fish did not differ before or during the fight. Siamese fighting fish are popular models for studying the neurological and physiological impact of certain chemicals, such as hormones , since their aggression is the result of cell signalling and possibly genes. Females were given testosterone, which resulted in changes to fin length, body coloration and gonads that resembled typical male fish.
In contrast, the female fish who were kept isolated did not continue to exhibit the male typical behaviours after testosterone was discontinued. The researchers concluded that exposure to these chemicals can negatively affect the mating success of male Siamese fighting fish. Siamese fighting fish were selected as prime models due to having comparable serotonin transporter pathways, which accounts for their aggression.
It was found that when exposed to fluoxetine, male Siamese fighting fish exhibited less aggressive behaviour than is characteristic of their species. Current understanding is so limited that there is little evidence for the genetic basis of basic traits, including sex determination.  A recent review article  argued for increased scientific investigation into the genome of the Siamese fighting fish, and listed several areas of interest which are paraphrased below:
Lastly, the betta fish is an excellent candidate for a model organism , particularly for aggression and pigmentation development, due to their extreme phenotypes in these areas.  Notably, the mitochondrial genome for the peaceful betta, P. imbellis , has also been sequenced,  potentially allowing for meaningful comparison between species in the future.  Past efforts to differentiate Betta species have been based on observable morphology , but given their visible similarity, this approach has masked much of the cryptic diversity in the genus.
 These studies have identified dozens of candidate genes in their respective model organisms which could serve as starting points for research into aggression in betta fish. The genetic basis for the synthesis and regulation of pigmentation in teleost fish is generally poorly understood,  and bettas are no exception. Later experiments confirmed the presence of genetic variation in hatchery stocks in Thailand, with low average numbers of alleles per locus and high heterozygosity rates.
He added that credible records show that pla kat of the Betta splendens species are native to Thailand and were first collected for fighting during the reign of King Rama III .  A scene in the James Bond film From Russia with Love shows three Siamese fighting fish in an aquarium as the villain Ernst Stavro Blofeld likens the modus operandi of his criminal organisation, SPECTRE , to one of the fish that observes as the other two fight to the death, then kills the weakened victor. “Capacitating the local farmers to enhance global marketing of Thailand’s national aquatic animal, the Siamese fighting fish” (PDF) .
“Artificial selection for male winners in the Siamese fighting fish Betta splendens correlates with high female aggression” . “Social Organization and Aggression Within Small Groups of Female Siamese Fighting Fish, Betta Splendens”. “Courtship By Subordinate Male Simease Fighting Fish, Betta Splendens: Their Response to Eavesdropping and Niave Females”.
“Male Siamese Fighting Fish, Betta Splendens, Increase Rather Than Conceal Courtship Behaviour When a Rival is Present”. ^ Vu, Trieu-Duc; Iwasaki, Yuki; Shigenobu, Shuji; Maruko, Akiko; Oshima, Kenshiro; Iioka, Erica; Huang, Chao-Li; Abe, Takashi; Tamaki, Satoshi; Lin, Yi-Wen; Chen, Chih-Kuan (17 June 2020). ^ Yang W, Wang Y, Zhu C, et al. De novo transcriptomic characterization of Betta splendens for identifying sex-biased genes potentially involved in aggressive behavior modulation and EST-SSR maker development.
^ a b c d e f Srikulnath, Kornsorn; Singchat, Worapong; Laopichienpong, Nararat; Ahmad, Syed Farhan; Jehangir, Maryam; Subpayakom, Navapong; Suntronpong, Aorarat; Jangtarwan, Kornsuang; Pongsanarm, Tavun; Panthum, Thitipong; Ariyaraphong, Nattakan (February 2021). “Overview of the betta fish genome regarding species radiation, parental care, behavioral aggression, and pigmentation model relevant to humans” . “Behavioral consequences of dietary exposure to crude oil extracts in the Siamese fighting fish (Betta splendens)” .
“Fluoxetine inhibits aggressive behaviour during parental care in male fighting fish (Betta splendens, Regan)” . “Chromosome-level reference genome of the Siamese fighting fish Betta splendens, a model species for the study of aggression” . ^ Ahmad, Syed Farhan; Laopichienpong, Nararat; Singchat, Worapong; Suntronpong, Aorarat; Pongsanarm, Tavun; Panthum, Thitipong; Ariyaraphong, Nattakan; Bulan, Jakaphan; Pansrikaew, Tanawat; Jangtarwan, Kornsuang; Subpayakom, Navapong (1 October 2020).
^ Panijpan, Bhinyo; Kowasupat, Chanon; Laosinchai, Parames; Ruenwongsa, Pintip; Phongdara, Amornrat; Senapin, Saengchan; Wanna, Warapond; Phiwsaiya, Kornsunee; Khne, Jens; Fasquel, Frdric (December 2014). “Southeast Asian mouth-brooding Betta fighting fish (Teleostei: Perciformes) species and their phylogenetic relationships based on mitochondrial COI and nuclear ITS1 DNA sequences and analyses” . ^ Vu, Trieu-Duc; Iwasaki, Yuki; Shigenobu, Shuji; Maruko, Akiko; Oshima, Kenshiro; Iioka, Erica; Huang, Chao-Li; Abe, Takashi; Tamaki, Satoshi; Lin, Yi-Wen; Chen, Chih-Kuan (17 June 2020).
“Genetic variation in different varieties of Siamese fighting fish using isoelectric focusing of sarcoplasmic proteins” . “Allozyme revealed substantial genetic diversity between hatchery stocks of Siamese fighting fish, Betta splendens, in the province of Nakornpathom, Thailand” . ^ Amparyup, Piti; Charoensapsri, Walaiporn; Samaluka, Nusree; Chumtong, Parichat; Yocawibun, Patchari; Imjongjirak, Chanprapa (April 2020).
Wild Betta fish habitat
Betta fish in the wild are typically found in shallow bodies of water stuffed with vegetation, such as rice paddies and swamps. However, it’s important to remember that though shallow, these pools are vast. As such, Bettas living in puddles is an absolute myth! The only time you’ll find wild Bettas living in puddles is when their territories have dried up.Since Bettas have a specialized organ called the labyrinth organ, they can survive in oxygen-poor water and will hop from puddle to puddle in search of new homes if the situation becomes dire. This is a last resort however, and fish can easily die in the process. As such, the idea that Betta fish can be kept in tiny bodies of water without consequences is unfortunately incorrect (more info in “Why Betta bowls are bad“).The tropical climates within the Betta’s natural range creates a wide variety of water conditions. Temperatures can range from 59 degrees Fahrenheit (15 °C) in the winter to 104 degrees (40 °C). in the summer. The pH varies as well from, with waters ranging from highly acidic to relatively alkaline. Hardness can be anywhere from very soft to hard or even brackish (withThe Betta complex’ upturned mouth reveals the diet the species has adapted to. Betta fish in the wild are insectivores, primarily eating midge fly larvae (bloodworms), as well as other larvae (mosquito, for example) and insects. They will also consume smaller fish and fry, if given the chance.Wild Bettas that are captured and raised in captivity can be trained to accept other types of foods as well, such as flakes and pellets. Domestic Bettas will take these food types with no issue. You can learn more about feeding domestic Bettas in the article on feeding Betta fish.Although hobbyists have been passing on stories of Betta fish for centuries, the exact history of how domestic Bettas came to be is not altogether clear because of scarce documentation. Fortunately, because of the sheer passion of hobbyists digging back through the ages, we do at least have an idea, even if some of the exact details are muddy.
Early history: origins
As it was mentioned earlier, it’s commonly believed that Betta fish originate from Thailand, where wild males were first caught and bred for fighting. The sport became so popular, and the gambling so rampant, that the king of then Siam, Rama III, taxed these fights. The king himself was passionate about the sport and presented a pair of his prized fish to a man named Dr. Theodore Cantor in 1840. Cantor initially gave these fish the scientific name of
A Fighting Fish Throughout History
Bettas have always been used as fighting fish, bred for their aggressive nature and, later, for their brilliant colors. In fact, it was a tradition for Malaysian children to pluck the fish from their homes, sometimes 50 at a time, and pit them against each other in fish fights for local bragging rights. Bettas of the 1800s and 1900s were dark and muddy-colored, turning vibrant shades when agitated. It’s only present-day betta fish that come in all the colors of the rainbow.The majority of betta fish that you’ll find pet stores in the Untied States come from commercial betta farms based in Malaysia and Singapore. Bettas are widely available at pet stores nationwide for between three and ten dollars per fish, depending on the type and fin shape. If you’re looking for a rare color or prized fighting fish, however, you can expect to pay more and you’ll have to seek out a breeder.
Habitat of the Betta Fish
Betta fish are native to the rice paddies, canals, floodplains and drainage ditches of Southeast Asia, most notably Thailand, Vietnam, Malaysia, Laos and Cambodia. Bettas are simple creatures, even for fish, and don’t require much décor in their tanks. While betta fish call Southeast Asia home, they are an invasive species and have been found in rivers and lake systems around the world.Bettas are labyrinth fish, meaning they have the ability to breathe oxygen directly from the air or from their gills. This unique ability is a result of the cyclical droughts and floods common to Southeast Asia and explains why bettas are able to tolerate small spaces and poor water quality (though changing your betta’s water regularly is recommended). Even though many bettas are sold in one-gallon tanks, try to keep your betta in a 2.5-gallon tank or larger.Betta fish typically live in warm water (75 degrees Fahrenheit or warmer), and can be fed a diet of betta fish pellets and frozen food including brine shrimp, bloodworms and daphnia. In the wild, betta fish eat insects and small crustaceans. They generally live between two and five years in captivity.
Siamese fighting fish
TheSiamese fighting fish are endemic to the central plain of ThailandBettas are well known for being highly territorial, with males prone to attacking each other if housed in the same tank; without a means of escape, this will usually result in the death of one or both fish. Female bettas can also become territorial towards one another in confined spaces.In addition to its worldwide popularity, the Siamese fighting fish is the national aquatic animal of Thailand,
Outside Southeast Asia, the name “betta” is used specifically to describeEnglish-speakers sometimes mispronounce betta as “bay-tuh”, after the second letter in the Greek alphabet. However, it is believed the name is derived from the Malay wordAnother vernacular name for Siamese fighting fish isSiamese fighting fish were originally given the scientific name
Distribution and habitat
According to Witte and Schmidt (1992),Wherever they are found,The tropical climate of the betta‘s natural habitat is characterised by sudden and extreme fluctuations in water availability, chemistry, and temperature.Wild bettas prefer to live in bodies of water teeming with aquatic vegetation and surface foliage, such as fallen leaves and water lilies.
The betta‘s worldwide popularity has led to its release and establishment in similarly tropical areas, including southeast Australia, Brazil, Colombia, the Dominican Republic, southeast United States, and Singapore.In January 2014, a large population of bettas was discovered in the Adelaide River Floodplain in the Northern Territory, Australia.
Due to their popularity, Siamese fighting fish are highly abundant in captivity. However, wild specimens are categorised by the IUCN as vulnerable, indicating the species is likely to become endangered without conservation efforts.
Bettas can be fed a varied diet of pellets, flakes, or frozen foods like brine shrimp, bloodworms, daphnia and many others. Due to their short digestive tracts—a characteristic of most carnivores—bettas have difficulty processing carbohydrates such as corn and wheat, which are commonly used as fillers in many commercial fish foods.Bettas are susceptible to overfeeding, which can lead to obesity, constipation, swim bladder disease, and other health problems; excessive food may also pollute the water. It is generally advised to feed a betta at least once daily, with only the amount of food it can eat within 3–5 minutes; leftover food should be removed.Some sources recommend that bettas undergo a “fast” for at least one day to allow food to be fully processed.
Reproduction and early development
If interested in a female, male bettas will flare their gills, spread their fins and twist their bodies in a dance-like performance. Receptive females will respond by darkening in color and developing vertical lines known as “breeding bars”. Males build bubble nests of various sizes and thicknesses at the surface of the water, which interested females may examine. Most 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. With each deposit of eggs the male releases milt into the water, and fertilisation takes place externally. During and after spawning, the male uses his mouth to retrieve sinking eggs and place them in the bubble nest; during mating some females assist their partner, but more often will simply devour 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 fall 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,
Information on precisely how and when Siamese fighting fish were first domesticated and brought out of Asia is sparse.
Some people in Malaysia and Thailand are known to have collected wild bettas at least by the 19th century, observing their aggressive nature and pitting them against each other in gambling matches akin to cockfights. In the wild, betta spar for only a few minutes before one fish retreats; domesticated betta, bred specifically for heightened aggression, can engage for much longer, with winners determined by a willingness to continue fighting; once a fish retreats, the match is over. Fights to the death were rare, so bets were placed on the bravery of the fish rather than its survival.The popularity of these fights garnered the attention of king of Siam (Thailand) who regulated and taxed the matches, and collected fighting fish of his own. In 1840, he gave some of his prized fish to Danish physician Theodore Edward Cantor, who worked in the Bengal medical service.
While it is unclear when bettas became popular in the aquarium trade, the early 20th century marked the first known departure from centuries of breeding bettas for aggression, to instead selecting for colour, finnage, and overall beauty for ornamental purposes.In 1967, a group of betta breeders formed the International Betta Congress (IBC), the first formal interest group dedicated to Siamese fighting fish. The IBC aimed to breed varieties that would be healthier and more symmetrical in fins and body shape, with an emphasis on animal welfare.
As tropical fish, bettas prefer a water temperature of around 75–82 °F (24–28 °C), but have been observed surviving temporarily at extremes of 56 °F (13 °C) to 95 °F (35 °C). When kept in colder climates, aquarium heaters are recommended, as colder water weakens their immune system and makes them susceptible to certain diseases.Bettas are also affected by the pH of the water: a neutral pH of 7.0 is ideal, but slightly higher levels are tolerable.
Aquarium size and cohabitants
Despite frequently being displayed and sold in small containers in the pet trade, bettas do best in larger environments; while they can survive in cups, bowls, and other confined spaces, they will be much happier, healthier, and longer-lived in a larger aquarium.Although males bettas are solitary and aggressive towards one another, they can generally cohabit with many types of fish and invertebrates if there is adequate space and hiding places. However, compatibility varies based on the temperament of the individual betta, and it is advised to carefully supervise the betta‘s interaction with other fish. Tankmates must be tropical, communal, nonterritorial, and not have a similar body type or long flowing fins; coldwater fish like goldfish have incompatible temperature requirements, while aggressive and predatory fish are likely to nip at the betta‘s fins or erode their slime coat.Female bettas are less aggressive and territorial than males, and thus can live with a greater variety of fish; for example, brightly coloured or large-finned fish will not usually disturb a female. Generally, female fighting fish can also tolerate larger or more numerous tankmates than males.It is not recommended to keep male and female bettas together, except temporarily for breeding purposes, which should always be undertaken with caution and supervision.
Bettas are fairly intelligent and inquisitive, and thus require stimulation; otherwise they can become bored and depressed, leading to lethargy and a weaker immune system.Indian almond leaves are increasingly popular for providing something closer to the natural foliage under which bettas would hide in the wild. Their tannins allegedly confer several health benefits,
Health and wellness
When properly kept and fed a correct diet, Siamese fighting fish generally live between three and five years in captivity, though in rare cases may live as long as seven to ten years.Like all tropical fish in captivity, bettas are susceptible to several kinds of diseases, usually caused by bacterial, fungal, or parasitic infections. Most illnesses result from poor water quality and cold water, both of which weaken the immune system.If betta fish are kept in communal tanks, fin nipping from other fish can lead to the onset of fin rot and this can make it more difficult to diagnose.
Over a century of intensive selective breeding has produced a wide variety of colours and fin types, and breeders around the world continue to develop new varieties.
Aggression in females
Wild bettas exhibit strong colours only when agitated. Over the centuries, breeders have been able to make this coloration permanent, and a wide variety of hues breed true. Colours among captive bettas include red, orange, yellow, blue, steel blue, turquoise/green, black, pastel, opaque white, and multi-coloured.The betta‘s diverse colours are due to different layers of pigmentation in their skin. The layers, from deepest within to the outermost,, consists of red, yellow, black, iridescent (blue and green), and metallic (not a colour itself, but reacts with the other colours). Any combination of these layers can be present, leading to a wide variety of colours within and among bettas.The shades of blue, turquoise, and green are slightly iridescent, and can appear to change colour with different lighting conditions or viewing angles; this is because these colours (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 colour patterns such as marble and butterfly, as well as metallic shades like copper, gold, or platinum, which were obtained by crossingSome bettas will change colours throughout their lifetime, a process known as marbling, which is attributed to a transposon, in which a DNA sequence can change its position within a genome, thereby altering a cell.
There has been much research in the courtship behaviour between male and female Siamese fighting fish. Studies generally focus on the aggressive behaviours of males during the courtship process. For example, one study found that when male fish are in the bubble nest phase, their aggression toward females is quite low. This is due to the males attempting to attract potential mates to their nest, so eggs can successfully be laid.One study considered the ways in which male Siamese fighting fish alter their behaviours during courtship when another male is present. During this experiment, a dummy female was placed in the tank. The researchers expected that males would conceal their courtship from intruders; instead, when another male fish was present, the male was more likely to engage in courtship behaviours with the dummy female fish. When no barriers were present, the males were more likely to engage in gill flaring at an intruder male fish. The researchers concluded that the male was attempting to court the female and communicate with its rival at the same time.
Metabolic costs of aggression
Studies have found that Siamese fighting fish often begin with behaviours that require high cost, and gradually decrease their behaviours as the encounter proceeds.
Behavioural effects of chemical exposure
Siamese fighting fish are popular models for studying the neurological and physiological impact of certain chemicals, such as hormones, since their aggression is the result of cell signalling and possibly genes.One study investigated the effect of testosterone on female Siamese fighting fish. Females were given testosterone, which resulted in changes to fin length, body coloration and gonads that resembled typical male fish. Their aggressive behaviour was found to be elevated when interacting with other females, but reduced when interacting with males. The researchers then allowed the females to interact with a control group of unaltered females; when the female fish stopped receiving testosterone, those who were exposed to the normal females still exhibited male-typical behaviours. In contrast, the female fish who were kept isolated did not continue to exhibit the male typical behaviours after testosterone was discontinued.Another study exposed male Siamese fighting fish to endocrine-disrupting chemicals. The researchers were curious if exposure to these chemicals would affect the ways in which females respond to the exposed males. It was found that when shown videos of the exposed males, the females favoured those who were not exposed to the endocrine-disrupting chemicals, and avoided those males that were exposed. The researchers concluded that exposure to these chemicals can negatively affect the mating success of male Siamese fighting fish.A psychology study used male Siamese fighting fish to investigate the effects of fluoxetine, an SSRI used primarily as an antidepressant in humans. Siamese fighting fish were selected as prime models due to having comparable serotonin transporter pathways, which accounts for their aggression. It was found that when exposed to fluoxetine, male Siamese fighting fish exhibited less aggressive behaviour than is characteristic of their species.
Phylogeny and cryptic diversity
Despite its commercial popularity, little is known about theAdditionally, betta fish have been used in several studies to assess the impacts of various environmental contaminants, including oil.Currently, the complete
The extreme genetically-driven aggression in fighting strains ofAt present, use of the betta fish as a model organism for studying aggression is in its beginning phases. Little is known about the genetic basis of aggression in betas, though differential degrees of aggression have been observed in different domesticated betta populations.
Research to date
There is evidence that the genetic basis for aggression in betta fish is not exclusively sex-linked – a recent study found that female bettas of the fighting strain show significantly higher levels of aggression than their female wild-type counterparts, despite the fact that historically only male bettas have been used in fights and thus artificially selected for aggression.A recent study found that a fighting pair of bettas will synchronise their gene expression profiles, with particular emphasis on 37 co-expression gene modules, some of which were only synchronised after a certain duration of time had been spent fighting.Work to identify the genetic basis for aggression has also been performed more generally in other model species, such as zebrafish.
Due to the incredible variation in pigmentation of adult bettas and visible pigment in developing embryos, bettas are an attractive model organism for studying the genetic basis for coloration.The genetic basis for the synthesis and regulation of pigmentation in teleost fish is generally poorly understood,
Work to date
In 1990, genetic differences (polymorphisms at several loci) were found between four different color varieties of bettas,Notable color phenotypes in
Other genetic work
Some of the few candidate genes identified in the literature specific to bettas are immune related genes, which were found in the first whole-body transcriptome of