In nature the betta originate in the shallow waters of canals, rice paddies and floodplains. Usually grows to a length of about 6.5 cm (2.6 in). Although aquarium specimens are widely known for their brilliant colours and large, flowing fins, the natural coloration of Betta are generally dull green, brown and grey, and the fins of wild specimens are short. In the wild, they exhibit strong colours only when agitated. In captivity, they have been selectively bred to display a vibrant array of colours and tail types.
Bettas are anabantoids, which means they can breathe atmospheric air using a unique organ called the labyrinth. This accounts for their ability to thrive in low-oxygen water conditions that would kill most other fish, such as rice paddies, slow-moving streams, drainage ditches, and large puddles.
The bettas exhibit two kinds spawning behaviour: some build bubble nests, such as B. splendens, while others are mouthbrooders, such as B. picta. The mouthbrooding species are sometimes called "pseudo bettas", and are sometimes speculated to have evolved from the nest-builders in an adaptation to their fast-moving stream habitats.
A phylogenetic study published in 2004 concluded tentatively that bubble-nesting was the ancestral condition in Betta, and that mouthbrooding has evolved on more than one occasion in the history of the genus. However it was unable to establish a correlation with any of three habitat variables studied: whether a species was found in lowland or highland streams, whether it was found in peat swamp forests, and whether it was found in water with fast or slow currents. Mouthbrooding species tend to exhibit less sexual dimorphism, perhaps because they do not need to defend a territory as the bubble-nesters do.
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 colour 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, Betta 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. Betta can reach sexual maturity at an age as early as 4–5 months.
In the aquarium
Water Condition
Betta prefer a water temperature of around 75–82 °F (24–28 °C) but have been seen to survive temporarily at the extremes of 56 °F (13 °C) or 95 °F (35 °C). When kept in colder climates, aquarium heaters are recommended.
Bettas are also affected by the pH levels of the water. Ideal levels for Bettas would be at a neutral pH (7.0) However, Bettas are slightly tolerant towards the pH levels. They have an organ known as the labyrinth organ which allows them to breathe air at the water's surface.
Even though Bettas do well in waters low in dissolved oxygen, that does not mean they require less oxygen than other fish. Bettas have a special respiratory organ that allows them to breathe air directly from the surface. In fact, they inherently must do so. In experiments where the labyrinth organ was removed, the fish died from suffocation even though the water was saturated with oxygen. For this reason, Bettas must have access to the water surface to breath air directly from the atmosphere. This organ was thought to allow the fish to be kept in unmaintained aquaria, but this is a misconception, as poor water quality makes all tropical fish, including betta, more susceptible to diseases such as fin rot.
Properly kept and fed a correct diet, Siamese fighting fish generally live between 3 and 5 years in captivity, but may live between 7 and 10 years in rare cases.
Food
Betta feed on zooplankton, crustaceans, and the larvae of mosquitoes and other water-bound insects. In captivity they can be fed a varied diet of pellets or frozen foods such as brine shrimp, bloodworms, daphnia and many others.
Despite myths that they will feed on any plant matter in the tank, they are naturally insectivores and do not typically or naturally consume vegetation.
Tank size & Mates
It is popular to keep betta fish in very small containers, such as bowls for display around the home. Contrary to popular belief, this can cause health issues and lead to an early death for the fish. Bettas prefer to be kept in larger tanks or community tanks. A commonly recommended tank size is 20 litres, or 5 gallons, and bigger is advisable, while 2.5 gallons is the minimum.
Males Betta cannot be kept together unless there are separators in the tank. Multiple females can generally be kept together without problems, and a single male can also be added to the mix. They can be kept with other peaceful species of fish and the fish that are bottom feeders, as long as they are small and are not fin-nipping types, such as Tiger Barbs. Male Bettas should not be kept with other fish that have similar body types and long fins, as they could mistake them for rivals.
Behaviour
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 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.
Comments