How Two Betta fighter Fish Behave in a Tank

With proper care, two betta fish can live together in harmony. However, it is important to be aware of the risks involved and to monitor the fish closely for signs of aggression.
Siamese fighting fish

Betta fish are native to Southeast Asia, where they live in shallow, stagnant water. They are thought to have been first domesticated in Thailand, where they were used in cockfighting-style competitions. Betta fish were introduced to the West in the late 19th century, and they quickly became popular aquarium fish.