Clown Fish Help

[r212019]

I have a mated pair of clown fish. They seem to be flapping their tails in the sand at the back of my tank. Is this something that they do when they are mating? It's kind of annoying that they are brushing my sand all over the place. They each take turns doing it. Take a look and let me know what you think.

Side note I just moved my leather today, thats why its kind of upside down

http://youtu.be/PQ-RSphSiHk