Ken I've had them now for 2 days, this is however my third set of a mated pair. They will eat the tube feet of almost any starfish and some urchins and I feed once maybe twice a month.
IPT nothing is wrong with your watchman when found in mated pairs one often turns that shade of grey that you are talking about, as far as the head of the watchman in the pic I was focused on the pistol as that is the best shot I have gotten of him to date.
Thank you strizzi16!