Egg-bound perhaps, or a tumor, or maybe just constipated. I don't know what to tell you. Fish are hard to treat if they aren't able to eat so we can get medication into them. Small fish are even harder to treat as in larger fish you can kinda rub them to see if its eggs or a tumor, but with smaller fish you'd squish them too easily. I think for now you should put her in some clean shallow water and see if she improves any.