When I first got my pastel he did this for a while, like the first week and a half or so. Sounds to me like it might be a little stressed. I would try and cover up some of his tank. Can he see another dragon? Maybee an older one. Sometimes we can be a little demanding of a new dragon, handle them a lot and don't give them the time to settle in and get into a comfortable pattern.. Also make sure he is getting his water. Mine does this sometimes when he's thirsty I offer it water and it perks them right up. Hope he comes around for you.