by Pullen Ken (Author) Betta fish, also called Siamese fighting fish, are small, colorful fish that are native to Southeast Asia and common in the pet trade. In Thailand, people call betta fish "pla kat," which means "fighting fish," and it couldn't be a more appropriate name. Male bettas are known fighters, aggressively flaring their gill covers and nipping at the fins of other males (or even females) who get too close. In the wild, fights may last only 15 minutes, but people in Thailand have bred bettas that are capable of fighting for hours.Bettas do well in captivity, and their aggression, which many find entertaining, along with their vibrant colors have helped make the species popular as pets worldwide.