Congratulations on your birth. I have seen a lot of newborn leos, and have never seen one born with such a large yok sac. I'd keep a close eye on it and look for signs of injury or infection. The yolk sac gives a quick route for bacteria to invade internally and cause infection. You may be better off keeping it in a bare bottom tank. The ray will probably not be as comfortable so it is a bit of a trade off, but you should be able to keep it cleaner. I'd love to know how long it takes to absorb a yolk sac that big.
Good luck.
Good luck.