IF left undisturbed by tank mates Kenya and Gsp can stay out all night as can most zoa's my Kenya stay upright all night my gsp if 50/50 as it's touchy with anything touching it or rubbing by from crabs fish etc. I'd be more worried if they didn't come out
Fill us in on some info like water parameters , tank history, things you feed or any additives you may dose, livestock etc anything you can think of but most importantly pics as to help us see what your seeing
cheers