Please research before buying your fish. If you aren't breeding, males and females will kill each other if in the same tank. Any betta will do that, and you will find yourself out of luck by trying to find a pair of bettas that can live with each other. They need their own seperate tanks. If you are breeding, you can't just buy two bettas and stick them in the same tank. You need two weeks, minimum, of conditioning. You also should not breed petstore bettas, as there are enough already.