BETTA FISH

All the Betta species are small fishes, but they vary considerably in size, ranging from under 2.5 cm (1 inch) total length in B. chanoides to 12.5 cm (5 inches) in the Akar betta (B. akarensis).^[1]
Bettas are anabantoids, which means they can breathe atmospheric air thanks to 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.^[2]
The various bettas can be divided into two groups, based on their spawning behaviour: some build bubble nests, like B. splendens, while others are mouthbrooders, like 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.^[3]

Food

Betta fish are not big eaters but should be fed a small amount once a day to once every other day.^[4] They can be fed floating flake food, freeze dried blood worms, live black worms, or frozen brine shrimp.
Betta pellets are small, round edible pellets that are food for most betta species. Betta pellets are made out of crude protein, crude fat, crude fiber, crude ash, moisture, phosphorus, certain vitamins, and other ingredients.

Name

There is often much confusion in terminology regarding these fish. Siamese fighting fish, B. splendens, are frequently sold in the United States simply as bettas. Fish fanciers are thus often unaware that, as of 2006, there are around 65 species classified within the genus Betta. A further source of confusion is that while the generic name Betta is italicized and capitalized, when used as a common name it is usually not capitalized.^[5] The common name of Betta pugnax, for example, is thus Penang betta.

Siamese fighting fish, B. splendens, is often referred to as betta in the U.S., leading to some confusion

The name Betta (or betta) is pronounced /ˈbɛtə/.^[5] That is, the first part is the same as the English word bet. By confusion with the name of the Greek letter beta, the name is often pronounced /ˈbeɪtə/ in American English, and may be misspelled with one t. The name of the genus is unrelated to that of the Greek letter, being derived from the Malay word ikan betah ("persistent fish").^[6]

Conservation

While many Betta species are common and B. splendens is ubiquitous in the aquarium trade, other bettas are threatened. The IUCN Red List classifies several Betta species as Vulnerable. In addition, B. livida is Endangered, and B. miniopinna, B. persephone, and B. spilotogena are Critically Endangered.^[7]
The United Nations Environment Programme lists an unconfirmed species, Betta cf. tomi, as having become extinct in Singapore between 1970 and 1994.^[8] This likely refers to the extirpated Singaporean population of B. tomi, which continues to exist in the wild in Indonesia and Malaysia as well as in captivity; the Red List classifies it as Vulnerable.^[9][10]

Species

A female Betta splendens

The currently described Betta species can be grouped into complexes for conservation purposes. (This grouping of species makes no claim at representing a phylogenetic reality.) The complexes of the associated species are:^{[1] [11] [12]}

• Akarensis complex:
  • Betta akarensis Regan, 1910 – Akar betta
  • Betta antoni Tan & Ng, 2006
  • Betta aurigans Tan & Ng, 2004
  • Betta balunga Herre, 1940
  • Betta chini Ng, 1993
  • Betta ibanorum Tan and Ng, 2004
  • Betta obscura Tan & Ng, 2005
  • Betta pinguis Tan and Kottelat, 1998

• Albimarginata complex:
  • Betta albimarginata Kottelat and Ng, 1994
  • Betta channoides Kottelat and Ng, 1994

• Anabatoides complex:
  • Betta anabatoides Bleeker, 1851 – giant betta
  • Betta midas Tan, 2009

• Bellica complex:
  • Betta bellica Sauvage, 1884 – slim betta
  • Betta simorum Tan and Ng, 1996

• Coccina complex:
  • Betta brownorum Witte and Schmidt, 1992
  • Betta burdigala Kottelat and Ng, 1994
  • Betta coccina Vierke, 1979
  • Betta livida Ng and Kottelat, 1992
  • Betta miniopinna Tan and Tan, 1994
  • Betta persephone Schaller, 1986
  • Betta rutilans Witte and Kottelat in Kottelat, 1991
  • Betta tussyae Schaller, 1985
  • Betta uberis Tan & Ng, 2006

• Dimidiata complex:
  • Betta dimidiata Roberts, 1989
  • Betta krataios Tan & Ng, 2006