Clown fish pre spawning dance

[Rodneybrick]

So I was checking out my tank tonite and noticed my clown fish doing this dance with each other. They were hanging around a particular flat piece of rock. I didnt notice anything on the rock but I guess it would be to small for the naked eye. If in fact the did lay fertilized eggs, how long before they hatch and what preperations should I make? Can someone shed some lifht on the subject.

 

[dannyp02908]

You can see the eggs. You will know when she will lay. There will be a protrusion on her belly.