I am very new to xenia and probably have no business posting a reply.
However, last Saturday I was fortunate to get a stock for free. Note that this stock was in a tank all comfy, then ripped from its home, put in a plastic baggy, transported to the meeting, lay around for a few hours while the speaker talked. Then, scooped up in his baggy, taken home to a new home. I acclimated him, and gently placed him on a rock that I thought he might like.
He/she is doing great! When lights are out, its all closed up. Withing a minute of the lights coming on, it's all waked up and its swaying and its little fingers are opening and closing to grab whatever there is to grab. Turn out the lights, and it just draws itself in, and sleeps I guess.
That being said, I think light is something to look at.