Betta Fish: I think my betta thinks it’s an egg

I feed my bettas the little fluval bug bites pellets and my make betta is in his own tank, usually far away from my females. However recently he’s had female company as I noticed one of my girls has been having a bit of weight gain and some odd looking poops. (Story for another time) so she’s in my hospital tank which is right next to the males. So he built this huge bubble nest and spent most of his time in the corner where his female neighbor was. Recently I was adding plants and cleaning the glass so I accidentally destroyed it. He built a new one last night and in the morning I fed them all as usual and I later came back to see a piece of food in his nest and all day he’s been guarding it when usually he likes to hide in his cave.