Questions - Need some input

I've had this brittle star for years, it has been in the present tank for over 2 years, never had any worries with it. today it looks like the top of the body has been removed, its now bright orange, used to be brown, like the legs. its still moving normally, I tried to reach in and pick him up but when I touched him he quickly scooted under the nearest rock. everything else in the tank seems to be fine as well.