Betta, Siamese Fighting Fish, Split-Tailed Betta, Libby Betta
The Betta or Siamese Fighting Fish is one of the most popular aquarium fish, and has been part of the hobby for a very long time!
The Betta or Siamese Fighting Fish Betta splendens is a very beautiful and vies with the highly favored Guppy Poecilia reticulata and the familiar Goldfish Carassius auratus for the title of best known fish. They are< also one of the oldest known freshwater fish to be kept in aquariums. They were collected before the 19th century in both Thailand and Malaysia. The Goldfish and their close cousin, the Paradise Fish Macropodus operculari, are perhaps the only species that have a longer history in the trade.
These fish are well known and greatly appreciated for their gorgeous appearance, interesting behaviors, and simple space requirements. Dubbed “the Jewel of the Orient”, they have been selectively bred across generations. Through selective breeding quite a number of different varieties have been developed sporting gorgeous colors, color patterns, and incredible fins. Other common names they are known by are Split-Tailed Betta and Libby Betta.
In their wild form, the Siamese Fighting Fish is dull green and brown in color and it has a stout elongated body with short rounded fins. The name “fighting fish” comes from the fact that males will most often fight each other until either one or both of them are dead. Short-finned males have long been bred in Thailand for fighting purposes, though in this sport the combatants are usually separated before a fatal outcome. They are ferocious fighters, yet interesting behaviors occur during combat. If one of them goes to the surface for air they will pause the conflict, and the other will not take advantage of its rival during this temporary helplessness. Also if there is a third male, it will wait its turn to fight the victor rather than joining in the fray between the other two.
The popular Betta, as it is known in the United States, is an equally combative Siamese Fighting Fish. Wild male Betta’s have short rounded fins and the beautiful specimens available in pet stores today have been developed from this wild variety. Their fins can be short to very long and flowing. The most commonly available are the Veil Tail Bettas but there are many others. Fancy Bettas range from those with a double tail fin to those with a crescent or half moon tail fin, and others with a crown design to all their fins. Only the male has the long fins though. The female’s fins will be shorter and females are generally more drab in color. When agitated both sexes will flare out their gills and fins making an impressive display, These captive bred aquarium specimens don’t lend themselves to a combative type of sport however. Their long flowing fins are very delicate and will actually fray if even the movement of the water is too fast.
Bettas are a great fish for a beginning aquarium enthusiast or for someone who wants minimal space and upkeep, but still wishes to enjoy a beautiful fish. Their needs are minimal in comparison to other species. They are quite disease resistant, very resilient, readily available, and inexpensive. They are hardy and will adapt to most aquarium conditions and their special ‘labyrinth organ’ enables them to survive in oxygen-depleted waters. Because of this they can survive in smaller spaces. A minimum sized aquarium for a single specimen would be 3 gallons if kept in a warm room, and with regular maintenance. They will do best however in a larger aquarium, a 10 gallon aquarium is recommended, and also allows room for other tankmates.
These are good community fish as long as the selection of tankmates is made with care. During and after nest building, the male is extremely aggressive and will regard anything that even remotely resembles a fish as a rival. This is especially true if it is similar looking fish (even a female), or a colorful fish. For this reason you can only keep one male per tank and you must select its companions carefully. They do fine in a community tank with fish that are very peaceful, similar in size, and more drab in color. Females can be kept in groups but males should be kept singly. Males can be kept in pairs or with several females if the tank is large enough and there’s lots of hiding places for the females.
For Information on keeping freshwater fish, see:
Freshwater Aquarium Guide: Aquarium Setup and Care
- Kingdom: Animalia
- Phylum: Chordata
- Class: Actinopterygii
- Order: Perciformes
- Family: Osphronemidae
- Genus: Betta
- Species: splendens
Betta fish – Quick Aquarium Care
- Aquarist Experience Level: Beginner
- Size of fish – inches: 2.8 inches (7.01 cm)
- Minimum Tank Size: 3 gal (11 L)
- Temperament: Peaceful
- Aquarium Hardiness: Very Hardy
- Temperature: 75.0 to 86.0° F (23.9 to 30.0° C)
Habitat: Distribution / Background
The Siamese Fighting Fish Betta splendens was described by Regan in 1910. This species is found in southeast Asia from the Lower Mekong Basin: Malayan peninsula, Thailand, Cambodia, and Vietnam. It occurs from the Mae Khlong to Chao Phraya basins, waters of the eastern slope of the Cardamom mountains, and from the Isthmus of Kra. Its natural range is Thailand, but in view of its popularity over the last 100 years it is difficult to ascertain its exact original range as it is now found living in the wild in many countries. The genus name “Betta” was taken from the Javanese name “Wuder Bettah”. This species is also called by the common name Betta, especially in the United States. Other common names include Split-Tailed Betta and Libby Betta.
They are called “pla-kad” by the natives, which literally means “biting fish”. Interestingly in Thailand they are called “pla kat Khmer” meaning “Fighting Fish from the land of Khmer” (Kampuchea). This then translates in English to “Fighting Fish from the country of Cambodia”. Khmer is the language of the Khmer people and the official language of Cambodia and Kampuchea is the official name of Cambodia.
This species is listed on the IUCN Red List as Vulnerable (VU). Although the exact extent of its occurrence is not fully known, much of the area surrounding its known habitats have been converted for heavy farming, leading to pollution and degradation. This is especially true in central Thailand. It is suspected that there is about a 30% decline in population across its range. Secondary threats could be a possible reduction of natural habitats as well as a genetic erosion due to escaped farmed species introduced back into the wild.
B. splendens is one of 70 currently recognized species in the Betta genus, and there’s another 6 or more undescribed species. This genus is comprised of two basic groups, bubble nest builders and mouth brooders. Further study may divide this group in the future, as mouth brooding is indicative of species that have evolved a good deal further. However currently they are all grouped together and in appearance the two groups are very similar.
Some of the other Betta species that are occasionally seen in the aquarium trade include:
- Giant Betta Betta anabatoides (Bleeker, 1851)
Other common names include: Pearly Betta, Large Unspotted Mouthbrooder, Giant Bettafish
- Slim Betta Betta bellica (Sauvage, 1884)
Other common names include: Slender Betta, Striped Fighting Fish, Slim Fighting Fish, Bellicose Fighting Fish, Green Jungle Fighting Fish, Slim Bettafish
- Browns Red Dwarf Fighter Betta brownorum (Witte & Schmidt, 1992)
- Wine-Red Betta Betta coccina (Vierke, 1979)
- Chameleon Betta Betta foerschi (Vierke, 1979)
Other common names include: Foersch’s Betta
- Crescent Betta Betta imbellis (Ladiges, 1975) Other common names include: Peaceful Betta
- Spotfin Betta Betta macrostoma (Regan, 1910)
Other common names include: Peacock Mouthbrooder, Brunei Beauty, Orangecheek Betta, Spotfin Bettafish
- Spotted Betta Betta picta (Valenciennes, 1846)
Other common names include: Painted Betta, Javan Mouth-Brooding Fighting Fish, Mouth-Brooding Betta, Spotted Bettafish
- Penang Betta Betta pugnax (Cantor, 1849)
Other common names include: Penang Mouth-Brooding Fighting Fish, Pengang Bettafish, Mouthbrooding Betta, Malayan Betta, Giant Betta, Big Eye Mouthbrooder, Javanese Mouthbrooding Finghting Fish
- Blue Betta Betta smaragdina (Ladiges, 1972) Other common names include: Emerald Betta, Blue Bettafish
- Borneo Betta Betta taeniata (Regan, 1910)
Other common names include: Banded Fighting Fish, Striped Betta, Borneo Bettafish
- Howong Betta Betta unimaculata (Popta, 1905)
Other common names include: One-Spot Betta, One Spot Mouthbrooder, Blue One Spot Mouthbrooder
Some Betta species that are a rare export in the aquarium trade include:
- Akar Betta Betta akarensis (Regan, 1910)
Other common names include: Sarawak Betta, Ladder-Fined Betta, Ladder Mouthbrooder
- Whiteseam Fighter Betta albimarginata (Kottelat & Ng, 1994)
- Balunga Mouthbrooder Betta balunga (Herre, 1940)
- Red Brown Dwarf Fighter Betta burdigala (Kottelat & Ng, 1994)
- Snakehead Fighter Betta channoides (Kottelat & Ng, 1994)
- Chini Mouthbrooder Betta chini (Ng, 1993)
- Green Throat Mouthbrooder Betta chloropharynx (Kottelat & Ng, 1994)
- Dwarf Mouthbrooder Betta dimidiata (Roberts, 1989)
- Edith’s Betta Betta edithae (Vierke, 1984) Other common names include: Edith’s Mouthbrooder
- Blue Band Mouthbrooder Betta enisae (Kottelat, 1995)
- Dusky Betta Betta fusca (Regan, 1910) Other common names include: Dark Betta, Brown Mouthbrooder
- Jealous Betta Betta lehi (Tan & Ng, 2005) Other common names include: Selangor Red Fighter
- Small Fin Fighter Betta miniopinna (Tan & Tan, 1994)
- Black Betta Betta patoti (Weber & de Beaufort, 1922)
- Dwarf Betta Betta persephone (Schaller, 1986) Other common names include: Black Small Fighter
- Threelined Mouthbrooder Betta prima (Kottelat, 1994)
- Beauty Mouthbrooder Betta pulchra (Tan & Tan, 1996)
- Toba Betta Betta rubra (Perugia, 1893) Other common names include: Red Sumatran Fighter
- Redish Dwarf Fighter Betta rutilans (Witte & Kottelat, 1991)
- Simor Fighter Betta simorum (Tan & Ng, 1996)
- Simple Mouthbrooder Betta simplex (Kottelat, 1994) Other common names include: Redfin Betta
Within the Betta genus, hybrids have been formed from cross-breeding the Siamese Fighting Fish B. splendens with the Crescent Betta B. imbellis, the Blue Betta Betta smaragdina, and the undescribed Betta sp. Mahachaia. Hybrids have also been reported between B. splendens and its close relative, the Paradise Fish Macropodus opercularis.
This species occurs in standing and slow-moving waters with thick vegetation. They are found in floodplains, canals, and rice paddies as well as medium to large rivers. They are Labyrinth fish, members of the suborder Anabantoidei often called Anabantoids, that can breathe atmospheric oxygen. These type of fish have an additional respiratory organ called the “labyrinth organ”, which allows them to survive in stagnant water bodies that have very low oxygen content or are even polluted. They are able to get oxygen by passing water through their gills, but also have the ability to gulp air at the surface.
They are primarily carnivorous, but they will feed on a variety of plants and animals. Their diet includes zooplankton, insect larvae, and crustaceans. as well as aquatic insects near the water surface and green algae.
- Scientific Name: Betta splendens
- Social Grouping: Solitary – In nature this species is primarily solitary, forming pairs when spawning.
- IUCN Red List: VU – Vulnerable
The natural Siamese Fighting Fish has a stout elongated body and short rounded fins, with the female having shorter fins than the male. Like all other labyrinth fish they can breath air, generally gulping it at the water’s surface. They have a special ‘labyrinth organ’ which acts like a lung that enables them to survive in oxygen-depleted or polluted waters. They will grow to between 2 1/2 to 3 inches (6 – 7 cm) in length and their average life span is 2 – 3 years with good care.
In their natural wild form the body coloration is a dull green and brown, though possibly becoming stronger they are agitated. There can be a color pattern change with mood swings, primarily on females. Horizontal bars will display when they are stressed or frightened (only rarely seen on males) and vertical stripes may appear on females when flirting to indicate they are willing and ready to breed.
Today Betta’s are available in many brilliant colors and color patterns, and with incredible fins. Both male’s and the female’s have been developed through selective breeding. This species has two primary mutation forms: a xanthorous form (an excess of yellow pigmentation) and a black form. and from these multiple varieties have been developed.
Blue and red colors were the first and easiest to develop. They have now been followed by magenta, orange, white, yellow, black, turquoise, dark blue, bright blue with pink highlights, cream, dark green colorations. Marble and butterfly patterns have emerged in combinations of these, such as a purple and blue. There are also metallic tones such as copper, gold, platinum, and an “Opaque” white. These were obtained by crossing B. splendens with other Betta species.
FINNAGE: Bettas have been selectively bred for finnage that is longer and of various shapes. Some of these forms include:
- Plakat Betta, Short-Finned Betta
This is the short finned fighting style Betta as found in the natural, wild form.
- Round Tail Betta, Single Tail Betta
These are single-tail Bettas that have fins with rounded edges. They are often confused with the Delta Tail Betta and even the Super Delta Tail Betta.
- Veil Tail Betta
The most common Betta is the ‘veil tail’. This fish has an extended finnage length, a non-symmetrical tail, and the caudal fin rays usually only split once. Veil tail finnage is also seen the well-known livebearers like the Molly, Platy, and Guppy as well as in Veiltail Goldfish.
- Crown Tail Betta, Fringetail Betta
On these the fin rays extended well beyond the membrane, giving the tail a crown appearance of a crown.
- Comb Tail Betta
This is a less extended version of the Crown Tail. It is developed by crossing a Crown Tail with another finnage type.
- Half-Sun Betta
This is a Combtail variety with caudal fin being 180 degrees, like on the Half-Moon Betta.
- Half-Moon Betta
This is where the caudal fin forms a “D” shape at a 180 degree angle, with edges that are crisp and straight.
- Delta Tail Betta
This variety has a caudal fin that is less than the 180 degree angle found on the Half-Moon, but it also has crisp and straight edges.
- Super Delta Tail Betta
This is basically an enhanced version of the standard Delta Tail, and some are just shy of being full Half-Moon Betta.
- Half-Moon Plakat Betta, Short-Finned Half-Moon Betta
This is a cross between the Plakat Betta and a Half-Moon Betta
- Over-Half-Moon Betta
This is a more extensive tail fin than found on the Half-Moon. Here the “D” shaped caudal fin is in excess of 180 degrees. It is developed crossing breeding Half-Moons, but sometimes the fins are too big for the fish, so causes the fish to swim improperly.
- RoseTail Betta
This is a beautiful Half-Moon Betta variation where there is so much finnage, that they overlap and look like the pedals of a rose.
- Double-Tail Betta
On this variety the dorsal fin is very elongated and the same length as the anal fin. The caudal fin is divided into two duplicate lobes.
- Elephant Ear Betta
Like the name describes, this Betta has very long, ear-like fins.
- Spade Tail Betta
This tail form is not seen as often since about the 90’s, but it is a caudal fin with a wide base that narrows to a delicate point, like a spade.
Fancy colorful males are most commonly seen, but females that were once quite a drab fish are now available in much more intense colors and finnage as well. Even so, females do not attain the same showy fins nor the color intensity that males of the same type do.
- Size of fish – inches: 2.8 inches (7.01 cm) – This fish will reach between 2 1/2 to 3 inches (6 – 7 cm) in length.
- Lifespan: 3 years – Their general life span is 2 – 3 years.
Fish Keeping Difficulty
This is a hardy fish and makes a good choice for the beginner. They are undemanding and because of their size can be kept in a smaller aquarium. They are hardy eaters and will readily accept a wide variety of foods. They are normally marketed as community fish, but take caution as the males will fight each other. Males should be kept singly or in pairs, but will be fine in a mixed community with other fish that are very peaceful, similar in size and with a less colorful appearance.
A handy cheat sheet that will benefit beginner betta keepers, and will likely hold some surprises for more experienced keepers as well, can be seen in the Betta Fish Care Infographic.
- Aquarium Hardiness: Very Hardy
- Aquarist Experience Level: Beginner
Foods and Feeding
Although the Siamese Fighting Fish are omnivores that will eat some green algae in nature, their diet is primarily carnivore. In the wild they feed mostly on zooplankton, insect larvae, crustaceans, and aquatic insects. In the aquarium they will generally eat all kinds of live, fresh, and dry protein foods. To keep a good balance give them a high quality protein pellet or flake food everyday. They will gladly eat foods designed for Bettas but also feed them brine shrimp (either live or frozen) or blood worms. Generally feed once or twice a day.
Confusion about the food requirements of these fish has come about in recent years. A trend where a glass vase topped with a plant to create a decorative environment, has lead people to think these fish eat the roots of plants. However they do not eat the roots of the plants and must be provided a protein diet.
- Diet Type: Omnivore – Although they will eat some green algae in nature, their diet is primarily carnivorous.
- Flake Food: Yes
- Tablet / Pellet: Yes
- Live foods (fishes, shrimps, worms): Some of Diet
- Meaty Food: All of Diet
- Feeding Frequency: Several feedings per day – Generally feed once or twice a day.
These are extremely hardy fish and although the labyrinth organ allows the fish to survive in oxygen depleted water, it is a common misconception that this makes water changes unnecessary. This is hardly the case as these fish will suffer the same tissue damage from built up toxins as any other fish. Regular water changes are a must with 25% weekly being recommended.
- Water Changes: Weekly – Weekly water changes of 25% are recommended.
The Betta or Siamese Fighting Fish will swim in all parts of the tank. This fish is quite hardy and will adapt to most aquarium conditions. Like all other anabantoids their special ‘labyrinth organ’ enables them to survive in oxygen-depleted waters. Because of this they can survive in smaller spaces. A minimum sized aquarium for a single specimen would be 3 gallons if kept in a warm room, and with regular maintenance. They will do best however in a larger aquarium, with adequate filtration and a heater, along with regular maintenance. A 10 gallon aquarium is recommended. Provide gentle water circulation and some sturdy aquarium plants. The aquarium should be covered to prevent jumps.
The tank should be decorated in a way which allows both the dominant and quieter personality type fish to live happily. This means the construction of a few hiding places and some surface cover. They will show their colors best on a dark substrate and need some sturdy aquarium plants to provide the female with places of hide. This species appreciates some cover with floating plants, but be sure to leave some open areas for them to gulp water at the surface.
This species is often subjected to tanks as small as 1/4 gallon, but this set up is very rough on the fish. While the fish is equipped with a labyrinth organ that allows the fish to survive in oxygen depleted waters for short periods of time, this fish will suffer the same tissue damage from ammonia and nitrate spikes as any other species. This is nearly impossible to prevent in an very small tank.
- Minimum Tank Size: 3 gal (11 L) – One male can be kept in a 3 gallon tank, but a pair or in a community it will do best in a 5 – 10 gallon aquarium.
- Suitable for Nano Tank: Yes
- Substrate Type: Any
- Lighting Needs: Moderate – normal lighting
- Temperature: 75.0 to 86.0° F (23.9 to 30.0° C) – Keep the surrounding room temperature consistent with the water temperature to avoid causing trauma to the labyrinth organ.
- Breeding Temperature: 80.0° F – Optimal breeding temperatures range between 79 -82° F (26-28° C).
- Range ph: 6.0-8.0
- Hardness Range: 5 – 35 dGH
- Brackish: No
- Water Movement: Weak – Will be uncomfortable with strong water currents.
- Water Region: All – These fish will inhabit all levels of the aquarium.
Generally it is considered a good community fish, however the Betta can get picked on. This fish cannot be housed with fin nipping fish. Other tanks mates will sometimes keep nudging it as if though to get it moving, and sometimes the fins become an easy target for an occasional nip. It has been noted that occasionally a Betta will attack other tank mates. This generally seems to be a case of misidentification, usually it’s a brightly colored platy or molly.
Male specimens are all but completely intolerant of each other and anything they mistake for another male Betta. The females are less aggressive towards each other but are still very hierarchal. Only one male can be kept in a tank as two males together will fight to the death. Females can be kept with each other, groups of 3 to 7 work well. A male can be kept with females if the tank is quite large and there are plenty of hiding places, however this is not generally recommended except when breeding, as they will often attack each other.
A mix of neutral personalities of fish, that are not similar in looks, is an ideal goal for the range of tank mates. Be careful in selections as tank mates need to be very peaceful. Good tankmates include some of the characins species like the Neon Tetra, Cardinal tetra, and White Cloud Mountain Minnow; some of the smaller loaches like the Kuhlii species; Coryadoras catfish; Platies; and even African dwarf frogs. Avoid other species that are colorful or have long, flowing fins.
- Venomous: No
- Temperament: Peaceful
- Compatible with:
- Same species – conspecifics: Sometimes – Males should not be kept together as they will fight, but females can normally be kept in groups or 3 – 7. Pairs can be kept together when breeding, but otherwise they may attack each other.
- Peaceful fish (): Safe – The Betta are peaceful with other peaceful fish of similar size, but avoid similar looking, colorful fish.
- Semi-Aggressive (): Threat
- Aggressive (): Threat
- Large Semi-Aggressive (): Threat
- Large Aggressive, Predatory (): Threat
- Slow Swimmers & Eaters (): Threat
- Shrimps, Crabs, Snails: Threat – is aggressive
- Plants: Safe
Sex: Sexual differences
Determining the gender of a Betta is generally quite easy, but sometimes they look similar enough to make a decision challenging. The male is brightly colored and has long colorful fins. Female’s have shorter fins and are rather drab in color. Females will develop a pale color to the belly when filled with eggs, and they may display horizontal striping when ready to spawn. Keep in mind that juvenile fish may not display sexual differences. Ideally, compare mature specimens of the same species and color, and compare multiple factors rather than using a single trait to determine sex.
Breeding / Reproduction
Like most fish in the labyrinth fish family, the Siamese Fighting Fish are bubble nest builders. Breeding this species is not difficult though the male will defend his nest to the death. Getting Bettas to spawn is very easy, but the actual raising of the young is incredibly challenging due to the accommodations which must be made. Care in housing for each specimen is necessary due to the aggressive tendencies of the males and there is frequently infection due to the delicateness of their fins. Breeding these fish should only be attempted by the most committed and informed enthusiasts.
Males will build bubble nests frequently, usually beneath a leaf. Prior to spawning they should be well conditioned with small offerings of live and frozen foods several times a day. When well fed, females should begin filling out with eggs, appearing very plump with a lighter colored belly and bars will often appear on the flanks.
An individual breeding tank with a tight fitting cover should be set up with the water level low, no more than 6 ” (15 cm) deep. Normal water parameters are fine, with optimal breeding temperatures ranging between 79 -82° F (26-28° C). During nest building a male will consider females to be rivals and bully them. Include some clumps of plants, like Java Moss, Hornwort or Milfoil, so the female will to have places for retreat. Floating plants like Ricca, stem plants grown to the surface, or any other floating debris will help keep the bubble nest in place.
Males will build the nest and then flare his gills and spread out his fins to entice the female to spawn. The female will darken in color and curve her body back and forth in response if she is receptive. The male will wrap his body around the female and the two will spawn with eggs and sperm being released simultaneously. With each spawn the female will release about 40 eggs. This behavior may be repeated several times, and if the female was well filled out, the spawn can be around 200 eggs. The eggs will mostly sink and the male will pick them up in his mouth and place them in his nest. The female may also help retrieve the eggs, but more often she simply eats any she finds. After spawning the male will chase off the female and will guard the nest and eggs until they hatch. The female must be removed after the eggs are produced or she will eat them.
The eggs will hatch in about 24 to 36 hours. After hatching the fry will remain in the nest for the next 2 to 3 days until they have absorb their yolk sacs and will then emerge and become free swimming. The male is usually removed from the breeding tank at this time or he might eat the fry which emerge from the nest, though this is not an absolute. Free swimming fry can be fed infusoria or a liquid fry food until they are large enough to eat baby brine shrimp. The juveniles exclusively use their gills for oxygen absorption until about 3 to 6 weeks, at which time their labyrinth organ becomes developed, and then they can begin to gulp air at the surface.
- Ease of Breeding: Difficult – Although getting Bettas to spawn is very easy, the actual raising of the young is incredibly challenging. This should only be attempted by the most committed and informed of enthusiasts.
Siamese Fighting Fish are very hardy so disease is not usually a problem in a well maintained aquarium. Some diseases they are prone to are bacterial infections, constipation and Hole in the Head if good water quality, nutrition, and maintenance is not provided. With any additions to a tank such as new fish, plants, substrates, and decorations there is a risk of introducing disease. It’s advisable to properly clean or quarantine anything that you want add to an established tank prior to introduction, so as not to upset the balance.
These fish are very resilient but knowing the signs of illness, and catching and treating them early makes a huge difference. An outbreak of disease can often be limited to just one or a few fishes if you deal with it at an early stage. The best way to proactively prevent disease is to give your fish the proper environment and a well balanced diet. The closer to their natural habitat the less stress the fish will have, making them healthier and happy. A stressed fish will is more likely to acquire disease. For information about freshwater fish diseases and illnesses, see Aquarium Fish Diseases and Treatments.
The Betta or Siamese Fighting Fish is readily available and inexpensive, though the more exotic varieties will be higher priced. Females usually cost less than males.