Perc clowns and strange behavior, could she be laying eggs?

[coralbeauty]

In my 37 gallon reef I have two perc clown who have been together for almost 4 years. As time has gone by one has become much larger than the other. As I expected would happen. They live in a huge hammerhead and which they actively defend at all times.
What is strange is that the larger of the two has been hanging out below the hammerhead and she keep creating a large depression in the LS. I filled it in this am when I was cleaning and she has already re-created it. Could she be thinking of laying eggs? For some reason I thought they laid their eggs in the rock??
I would love to hear from someone who's clown have mated...............
Thanks,
Connie

 

[coralbeauty]

Thanks so much for the quick answer. I will let her have her pit and see if she decides to fill it up with eggs.
Connie