The Siamese fighting fish (Betta splendens), commonly known as the betta, is a freshwater fish native to Southeast Asia.

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, while the fins are short; wild fish exhibit strong colors only when agitated. In captivity, Siamese fighting fish have been selectively bred to display a vibrant array of colors and tail types.
ベタ・スプレンデンス ปลากัด