Sand surfing?

When I set up the 10 gallon tank for the Betta last week, my mom wanted it to be the white sand bottom. Although it didnt work out in the big tank with the loaches, I tought it would be neat in the Betta tank. Ammonia 0, nitrites 0, nitrates 0. This evening Betta is belly surfing the sand. This is a very fine, soft feeling sand, like riding on a pillow. Should I worry, or let him enjoy himself?

If hes active, eating not clamped up i'd leave him be

He is active, eating, doesn't appear to be clamped or stressed..

I have seen my apisto's do the same in their sand, I think they just like it , although just keep a close check for any little white spots (Ick), but he would be rubbing and flicking a lot if it was that.