It's hard to tell without a lot of details, but maybe you are feeding her too much... :( You are probably overfeeding her. Try not feeding her for a few days- but don't worry bettas can survive without food for a whole week.
Your betta fish may have been impregnated before you got her.
Once the female Betta has been spawned out by the male she MUST be removed otherwise he will kill her.
No he hasnt
noooooooooooooooooooooooooooooooo!!!!!!!! never put a female in with him unless you have experienced with them for years like me and i still have dead females come out and i have done it for years
Consult your doctor.
it hasnt
During the courtship process, the male betta will often follow the female around the tank, flashing his fins as a show of display. It is not uncommon for the male betta to be mildly aggressive to the female. The male will also build a "bubble nest", which is essentially a mass of bubbles that float at the top of the water. When the female has been courted and is ready to lay eggs, she will lay her eggs in or near this nest. The male will then spend most of his time watching the nest and replacing any eggs that fall out. The female at this point has no role in the care for the fry.
YOu were born with one & if it hasnt been removed you have an appendix.
it hasnt.
The male will protect, tend, and clean the eggs after they have been laid. It's best to remove the female right after mating and the male after the babies are free swimming (3 or so days). The female will die if she is left in there and you could risk loosing your babies. Also after the baby's have hatched remove them from harm of the female or male. They will both tend to eat the fry's, or baby's.
They may just not have been doing it right, especially if they haven't been breed before. Practice practice practice.
No he hasnt. There was a rumour that was going around and it was not true.