Thanks for using Petco Pet Education Center, formerly Petcoach! It is difficult to know just based on one picture though he does look like a black German Shepherd. You can always proceed with the DNA test to check the breed which is available online. I would encourage you to have him evaluated by a veterinarian for further assessment to check for possible reasons of his perceived lack of growth. Your veterinarian would be able to obtain more information from you and also by doing a physical examination. Good luck and have a great day!