I don't know if you still are wondering or had any survive... But I have raised several batches of angels (koi also) in my tank. When I see the eggs or notice the behaviour that tells me they are coming, I usually put a divider in my tank if possible separating the parents and eggs, if they have already laid them. I will also put an air stone close enough to help create a current, but not close enough to disturb the parents fanning the eggs. I have never had an issue with the parents eating the eggs or fry...my loaches on the other hand love the eggs.
