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21 September 2020

National Aquatic Animal of Thailand — Siamese Fighting Fish (Betta splendens)

Thailand: National Aquatic Animal of Thailand – Siamese Fighting Fish (Betta splendens), 21 September 2020. Images from Thailand Post.

Technical Specifications:

TH-1197. The National Aquatic Animal of Thailand
First day of sale: 21 September 2563
Price: 5.00 baht (4 styles)
Number of prints: 500,000 each.
Size: 48 x 30 mm (Horizontal)
PHOTO: Betta splendens , which was declared as Thai National Aquatic Animal in BE 2562 (CE 2019), photographed by Mr. Phatthani Warm Moonlight.
5.00 Baht (type 1): Betta, national flag
5.00 Baht (type 2): Golden Elephant’s ear, long tail.
5.00 baht (type 3): Golden Pho leaf betta
5.00 Baht (type 4): Betta tail, national flag color.
Designer: Mr. Udon Thani Thammarat (Thai Post Office Ltd)
Printer: TBSP Public Company Limited
Printing Method: Multi-color offset lithography
Number of stamps per sheet: 10
First day cover price: 32.00 baht.
Miniature sheet: 40.00 baht (sold in 2 designs)

1197. ตราไปรษณียากรชุดสัตว์น้ำประจำชาติ
วันแรกจำหน่าย : 21 กันยายน 2563
ชนิดราคา : 5.00 บาท (4 แบบ)
จำนวนพิมพ์ : แบบละ 500,000 ดวง
ขนาด : 48 x 30 มม. (แนวนอน)
ภาพ : ปลากัดไทย (Betta splendens) ซึ่งได้รับการประกาศให้เป็นสัตว์น้ำประจำชาติไทย เมื่อปี 2562 ถ่ายภาพโดยนายพัชร อุ่นแสงจันทร์
5.00 บาท (แบบที่ 1) : ปลากัดสีธงชาติ
5.00 บาท (แบบที่ 2) : ปลากัดหูช้างสีทองหางยาว
5.00 บาท (แบบที่ 3) : ปลากัดหางใบโพธิ์สีทอง
5.00 บาท (แบบที่ 4) : ปลากัดหางมงกุฎสีธงชาติ
ผู้ออกแบบ : นายอุดร นิยมธรรม (บริษัท ไปรษณีย์ไทย จำกัด)
บริษัทผู้พิมพ์ : ทีบีเอสพี จำกัด (มหาชน)
วิธีการพิมพ์และสี : ลิโธกราฟี่ – หลายสี
จำนวนดวงในแผ่น : 10 ดวง
ซองวันแรกจำหน่าย : 32.00 บาท
แผ่นตราไปรษณียากรที่ระลึก : 40.00 บาท (จำหน่ายเป็นชุด จำนวน 2 แผ่น)

Betta, National Flag:

Golden Elephant’s Ear, Long Tail:

Golden Pho Leaf Betta:

Betta Tail, National Flag Colors:

Siamese Fighting Fish

The Siamese fighting fish (Betta splendens), also known as the betta, is a popular fish in the aquarium trade. Bettas are a member of the gourami family and are known to be highly territorial. Males in particular are prone to high levels of aggression and will attack each other if housed in the same tank. If there is no means of escape, this will usually result in the death of one or both of the fish. Female bettas can also become territorial towards each other if they are placed in too small an aquarium. It is typically not recommended to keep male and female bettas together, except temporarily for breeding purposes which should always be undertaken with caution.

This species is native to the Mekong basin of Thailand, Cambodia, Laos, and Vietnam and is mostly concentrated in the Chao Phraya river in Thailand. The fish can be found in standing waters of canals, rice paddies and floodplains. It is listed as Vulnerable by the IUCN. On 5 February 2019, Thailand’s council of ministers confirmed “Siamese fighting fish” as Thailand’s National Aquatic Animal.


B. splendens usually grows to a length of about 7 cm (2.8 in). Although aquarium specimens are widely known for their brilliant colors and large, flowing fins, the natural coloration of B. splendens is generally green, brown and grey, and the fins of wild specimens are short. In the wild, they exhibit strong colors only when agitated. In captivity, they have been selectively bred to display a vibrant array of colors and tail types.

A crowntail male

Conservation Status

Although popular as an aquarium fish, the IUCN has classified B. splendens in the vulnerable category. The fish is naturally endemic to Thailand and can be found in shallow areas in marshes or paddy fields. The primary threat is due to habitat destruction and pollution, as farmlands continue to be developed across central Thailand.

Reproduction and Early Development

Male bettas will flare their gills, spread their fins and twist their bodies in a dance if interested in a female. If the female is also interested she will darken in color and develop vertical lines known as breeding bars as a response. Males build bubble nests of various sizes and thicknesses at the surface of the water. Most tend to 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. If she is not removed from the tank then she will most likely be killed by the male.

The eggs will 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, 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.

A pair spawning under a bubble nest in a breeder’s tank

Fighting Fish

Some people of Thailand and Malaysia are known to have collected these fish prior to the 19th century from the wild which are line-bred for aggression in eastern Thailand.

In the wild, betta spar for only a few minutes before one fish backs off. Bred specifically for heightened aggression, domesticated betta matches can go on for much longer, with winners determined by a willingness to continue fighting. Once a fish retreats, the match is over.

Seeing the popularity of these fights, the king of Thailand, Rama III, 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 Theodore Edward Cantor, a medical scientist. Nine years later, Cantor wrote an article describing them under the name Macropodus pugnax. In 1909, the ichthyologist Charles Tate Regan, upon realizing a species was already named Macropodus pugnax, renamed the domesticated Siamese fighting fish Betta splendens.

The vernacular name “plakat“, often applied to the short-finned ornamental strains, is derived from the Thai word pla kat (Thai: ปลากัด), which literally means “biting fish” and is the Thai name for all members of the B. splendens species complex (as all members have aggressive tendencies in the wild and all are extensively line-bred for aggression in eastern Thailand) rather than for any specific strain(s) of the Siamese fighting fish. So the term “fighting fish” comes in use to generalize all the members of the B. splendens species complex including the Siamese fighting fish.

Aquarium Fish

In 1892, this species was imported to France by the French aquarium fish importer Pierre Carbonnier in Paris, and in 1896, the German aquarium fish importer Paul Matte in Berlin imported the first specimens to Germany from Moscow.

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 wetland wildlife.

A dalmatian orange male


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 genus Betta, intergeneric hybridizing of Betta splendens and Macropodus opercularis, the paradise fish, has been reported.

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. 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.


Wild fish exhibit strong colors only when agitated. 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.

Bettas are found in many different colors due to different layers of pigmentation in their skin. The layers (from furthest within to the outer layer) consists of red, yellow, black, iridescent (blue and green), and metallic (not a colour of its own, but reacts with the other colors to change how they are perceived). Any combination of these layers can be present, leading to a wide variety of colors.

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 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 colour patterns such as marble and butterfly, as well as metallic shades through hybridization like copper, gold, or platinum (these were obtained by crossing B. splendens to other Betta species).

Halfmoon male displaying his flared opercula

A true albino betta has been feverishly sought since one recorded appearance in 1927, and another in 1953. 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.

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

Koi bettas have mutated now and some are no longer marbles and do not change colors or patterns through out their lifetime (known as true Koi) attributed to the defective gene that causes marbling not being repaired in the color layers after a time.


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 can include when they are intimidated by movement or change of scene in their environments. Both sexes display pale horizontal bars if stressed or frightened. However, such colour changes, common in females of any age, are rare in mature males due to their intensity of colour. 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). Betta splendens enjoy a decorated tank, being a territorial fish it is necessary to establish territory even when housed alone. They may set up a territory centered on a plant or rocky alcove, sometimes becoming highly possessive of it and aggressive toward trespassing rivals. This is the reason why when kept with other fish the minimum tank size should be 45 litres (about 10 gallons). Contrary to popular belief, bettas are compatible with many other species of aquarium fish. Given the proper parameters bettas will be known to only be aggressive towards smaller and slower fish than themselves such as guppies.

The aggression of this fish has been studied by ethologists and comparative psychologists. These fish have historically been the objects of gambling; two male fish are pitted against each other to fight and bets are placed on which one will win. One fish will arise the victor, the fight continuing until one participant is submissive. These competitions can result in the death of either one or both fish depending on the seriousness of their injuries. To avoid fights over territory, 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 may lead to stress in some individuals. Not all Siamese fighting fish respond negatively to other males, especially when the tank is large enough for each fish to create their own designated territory.

A male Siamese Fighting Fish flaring at his reflection in a mirror. To replace the image in the Siamese Fighting Fish article. I held the mirror off to the left to have him flare at it and put a sunlight lamp over him to take the picture. He is in a classic drum-style fish bowl.

Aggressive Behavior in Females

In general, studies have shown that females exhibit similar aggressive behaviors as their male counterparts, but these behaviors are less common. A group of female Siamese fighting fish were observed over a period of two weeks. During these two weeks, the following behaviors were recorded: attacking, displays, and biting food. The results of this observational study indicated that when females are housed in small groups, they form a stable dominance order. For example, the fish who was ranked at the top showed higher levels of mutual displays, in comparison to the fish who were of lower ranks. The researchers also found that the duration of the displays differed depending on whether an attack occurred. The results of these studies indicate that female Siamese fighting fish should be considered as often as males, as there are evidently interesting variations in their behaviors as well.

Courtship Behavior

There has been numerous research in the area of courtship behavior between male and female Siamese fighting fish. This research has focused on the aggressive behaviors 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. It has also been found that in regards to mate choice, females often “eavesdrop” on pairs of male Siamese fighting fish while they are fighting. When females witness aggressive behavior between a pair of males, the female is more likely to be attracted to the male who won. In contrast, if a female did not “eavesdrop” on aggressive behavior between a pair of males, the female will show no preference in mate choice. In regards to the male fish, the “loser” fish are more likely to attempt to court the fish who did not “eavesdrop”. The “winner” fish have been found to show no preference in regards to female fish who “eavesdropped” and those who did not.

One study considered the ways in which male Siamese fighting fish alter their behaviors 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, however this surprisingly was not the case. It was found that when another male fish was present, the male was more likely to engage in courtship behaviors 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. Therefore, the researchers conclude that the male is attempting to court the female and communicate with the rival male present at the same time. These results indicate the importance of considering courtship behavior, as the literature has suggested there are many factors that can dramatically affect the ways in which both male and females can act in courtship settings.

Super Orange PKHM

In Popular Culture

The Fisheries Department of Thailand promotes pla kat, or Siamese fighting fish, as the national fish, which it declared in February 2019. Department chief Adisorn Promthep said that the proposal was submitted to the National Identity Office under the Prime Minister’s Office for approval. He said that once the status was recognized, fighting fish farming began to be promoted, which generates money and creates jobs. 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.

The titular character in the novel Rumble Fish and subsequent film adaptation is a Siamese fighting fish. In both, the character Motorcycle Boy is fascinated with the creatures and dubs them “rumble fish”. He speculates that if the fish were to be set free in the river, they wouldn’t behave so aggressively. A common misconception regarding keeping B. splendens is that they should live in vases or bowls. However, this has been proven to damage their health, life expectancy, and cause negative behavioral changes.

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 organization, SPECTRE, to one of the fish that observes as the other two fight to the death, then kills the weakened victor.

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