Bettas are native to Southeast Asia where the climate is tropical. The adequate water temperature for betta fish ranges between 25 and 28° Celsius. Unless you live in a tropical climate and don’t use air conditioning, then you probably don’t need one. It’s preferable that your aquarium’s water temperature remains within the range of 25 and 28° Celsius. If temperatures slightly fall below, your fish won’t die but it’ll become highly susceptible to deadly diseases. Monthly temperature ranges in Thailand Bettas are one of the most popular fish in the fishkeeping hobby but sometimes one of the most misunderstood as well. Over the years, pet stores have grossly misled their customers and dispersed many falsehoods regarding the level of care required by betta fish. This has been heavily criticized primarily, by the fishkeeping community and several animal protection groups.