You wait for them to hatch . . . Try to keep the water perams stable. If you have any loaches, corys, tetras, etc, remove them if you want to raise the fry and don't want them to be fish food. When and if they hatch, you can choose to siphon out the fry into a separate-but-equal tank. Try to have the same perams as you did in the parent tank. Feed them baby fish food when they lose their yolk. Just do some research on the web.