Mizuno Fireball Big Boy

Hi I am new here. We rescued a 16 week old Golden Doodle from a shelter in St. Louis in July. Now at 9 months, he is a great dog, but not without his challenges. I appreciate all the posts about behavior. I know with some work and maturity Mizuno will be a great boy! We also have a 12 year old dalmatian who rules the roost.