Lionfish Shedding ?

All,

I previously posted a note to ask what all these ghost like pieces of 'skin
like' material were floating around in my tank.

I now know what it is, as I saw my lionfish last night shedding his skin! he
was even shaking his entire body to get it off of him.

I have never read anything about this in online resources, books etc. Is
this normal / what does it mean?

Kind Regards,
David