Possible she's pregnant--looks pretty round. Just provide plenty of cover, like floating plants, and bushy plants, or plastic baby hides that look like plants, and they sell at Petco or Petsmart. Or order some online, like I did. I have some plastic floating plants too. Just keep her where she normally is (separating her might stress her out too much) and hope for the best. Sometimes all the babies are eaten no matter what you do. That's what happened to me. They are very small when born, so if you see any, you could buy a plastic "breeder" where the babies could stay until they are about a month old, and big enough so they won't get eaten by mama or other fish. They aren't expensive at all. They come with instructions, and they can be attached to the inside of your tank. I would just net any babies I saw, and put them in the breeder.