I left the light on in half the tank tonight, to make it easier for the Macropodus to keep track of the babies. As soon as I switched off the light in the other half of the tank, all of the platies (and several of the angels) moved into the lit half of the tank, brining them into what the consider their territory. That said, most of the platies ended up in the deep water below the nest, which the Macropodus ignore.
The nest is full of fry. Not sure what happens next - they are supposed to be free swimming by day 3. I'm not sure what happens then - if he will still protect them, and if he will be able to protect them.