"ribs" they have since turned brown and black and appear dead. will the flesh grow back?
What has turned black? The "ribs" or the flesh?
Keep an eye out for "brown jelly" the name describes it and you will know it if you see it. the brown jelly will consume the flesh of the entire coral over the course of a couple of days or less. While the coral is trying to repair itself, it is important to feed it, medium sized chunks of meaty foods should do fine (chopped shrimp or silversides or kill, etc...