Keep just giving it all sorts of food. Try everything and figure out what it's favorite is. I would try and put some feeders in there also. It might want them.....
I would feed in the morning and evening untill she fattens up again. I am sooo Jelouse of such a beautiful ray! the markings are amazing, I want to see pictures as she fattens up! GL on your ray! Lets hope you can save her! We are all pulling for you.