Sorry for the delayed reply.
The white tube is attached to a nano sponge filter bringing water up from the bottom. The gold tube is the overflow tube. It has a piece of fine mesh wrapped around and sticking above the water line to prevent fry from going in, hopefully. The top does hold water independently. Probably a airline down the overflow for water changes.
Its kind of inspired by Master Breeder Dean and his tray system.
As for the fry, I'll start with angels cuz they are already breeding. I don't know how long they will be there. First time trying it.