Dried out scales on back?

[guidofatherof5]

Also, why do they always poo as soon as you clean their tank?! Not even a couple hours after I finish, almost every time I do it! GAH!

That's just their way of saying thanks for all your hard work.

I think they are just trying to make it more their place. Scent marking if you will.
Of course, I have know proof that is what's going on. It just seem logical.