The first time that they spawned I was lucky enough to see them in action and it looked like they were both doing a different thing.
I have 5 angels, these 2 have paired off, Would they choose each other if they were both females?
That article was very interesting, I had a feeling it would take a while for the parents to raise a batch of eggs, but maybe next time they might let them get into wriggler stage.
I think I will get a piece of slate, cos every time they spawn its always on the filter and when I need to clean it out.