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''Betta'' is a large genus of small, often colorful, freshwater ray-finned fishes in the gourami family (Osphronemidae). By far the best known ''Betta'' species, however, is ''B. splendens,'' the Siamese fighting fish. ==Characteristics== All the ''Betta'' species are small fishes, but they vary considerably in size, ranging from under 2.5 cm (1 in) total length in ''B. chanoides'' to 12.5 cm (5 in) in the Akar betta (''B. akarensis'').〔 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.〔Marcus Song, ''Caring for Betta Fish'' Lulu Press, 2006. ISBN 1-4116-9365-5〕 The various bettas can be divided into two groups, based on their 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. 抄文引用元・出典: フリー百科事典『 ウィキペディア（Wikipedia）』 ■ウィキペディアで「Betta」の詳細全文を読む スポンサード リンク
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