Bettas originate in the shallow waters of Thailand, Indonesia, Malaysia, Vietnam, and parts of China.
Betta splendens is easily the most popular species of Betta bred and sold in the aquarium trade. These captive bred species have become significantly different than the original wild caught specimens they are derived from, having been bred to bring out specific features such as new varieties of tail and fin types as well as unique colours.
Bettas do not need a lot of room, their natural habitat is usually quite small and therefore they are not suitable for large aquariums as they can become exhausted, stressed and even die.
They require around a 2 litre capacity per fish as a general guideline but over 30 litres is too much space, at least one small plant or ornament for the fish to swim around, gravel to trap the fish waste which reduces the amount floating around.
Water treatment to remove chlorine, chloramine and ammonia is recommended and their environment should be kept around 25-27 degrees Celsius.
Bettas are anabantidae which means they can breathe oxygen directly from the air and therefore do not need a filter if they are housed by themselves.