First, you really should not keep a betta in a vase with a plant. Most of the time, some roots of the plant will start to decay and may develop a fungus under the water. This could mean death to your little betta friend. There are a lot of people who know how to keep aquarium plants with fish and have a healthy environment, but it usually doesn't work in a vase. Water quality can get bad easily and quickly in such a cramped environment, and that is not good for the fish. A tall/thin vase is especially not good for water quality, because oxygen enters water from the top, so a wider bowl would be better. Second, the amount of space/water that you have for one fish is really not adequate for two fish. And lastly, you should never keep female bettas with male bettas. He will eventually kill her (especially in such a small space). And if they do spawn before that happens, you will have a lot of dead eggs/babies on your hands. You really should not attempt to breed them unless you know your stuff. I just want to add that I think it is sad the way pets stores market bettas in vases. It is sad for the betta as well as it's owner, because many aren't able to live out their full life. Your betta is lucky because you're asking questions. Good luck!