If they are young it is natural for a gecko that just reached its adult size to have a drastically smaller metabolism and not eat in front of you. I never see my male eat but his body weight remains right. I have commonly heard that it is important for the male to be larger for a pair to be compatible but my experience is limited so i would just rely on your geckos appearance as an indication of health. In the picture he looks robust though. Thanks for the compliment!