angel relationships

My angelfish attempted breeding again- I say 'attempted' because they're all female, so when two pair off, one lays eggs and the other just protects the area from the third. (My kids think it's hilarious that I have lesbian fish). They usually only do this when food is rich- if I've been giving them flies or frozen mysis shrimp, etc. It's always been Miss Beautiful and the golden Precious before, with Precious laying the eggs. This time I was surprised- after some threats and chasing around the tank (which I didn't pay much attention to) in the previous week, Miss Beautiful paired off with Shirley, and my older angel laid the eggs

on aponogeton bolivianus leaf.

Shirley helped clean the leaf and chase Precious away on the first day. Next day shirked her duties and hung out in the opposite corner,

while Miss Beautiful continued to fan the eggs futilely. A day later they were eaten, of course. It made me sad to watch Miss Beautiful working so hard, with her truncated pectoral fins. (She hasn't run into the walls for a very long time now, but they never grew back completely after the last time were damaged).

I'm curious why they switched pairs, and also why Miss Beautiful was the one to lay this time- but of course I'll never know. Did Miss Beautiful get tired of Precious? Did she decide it wasn't working so time to change partners? Is she dominant in the pairing with Shirley, so she got to lay this time? No idea how they work that out between them, just interesting to think about.