I will bet money he is like that because he is with the other. Who knows what she is doing to him when you aren't looking. Also mav is right about the sand. Be sure that he is pooing. Also be sure to give him a bath every other day right now till he eats. Probably a little dehydrated as well. In the interim....do you have anything that will double as a little tank or a critter carrier you could put him in? My concern is she will kill him. They will eat another beardie if they can.