Are my Royal Grammas getting ready?

I jsut noticed this morning that my largest Royal Grama has built a "nest" out of vegetation in a large hole in my rockwork. There is a small entrance that he's fashioned, and all in all it looks just like a weaver birds nest, but stuffed in a hole. When I turned the lights on, he swam over the the smaller RG, did a couple of fast close circles around her, then swam into the hole. She waited about 5 seconds, then slowly followed.

Does this sound like some hanky-panky will shortly ensue?
 
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