They may, but they don't usually fight if they are given enough room for them to live in reasonably. ie 1 inch of fish needs a minimum of 1 gallon of water. So 2 female Bettas would need a minimum sized tank of around 5 gallons nominal.
Mainly for territorial and mating purposes. Bettas are very territorial and will attack any fish with bright colors and large fins. Especially other Bettas. Bettas flare when threatened by opening...
Male betas are aggressive towards other males. They will fight each other, and that could lead to death. You can have females in the same tank as males, however, they will most likely mate and hatch...
Betta fish are otherwise known as Siamese Fighting Fish. They originate from Thailand, Cambodia, Vietnam and Myanmar, primarily Thailand. Often found in still or slow-moving water such as rice...