Hello! I have an adorable 9 week old golden who we brought home a week ago. I have a 6 year old extremely lazy/submissive Velcro golden who has shown absolutely zero interest in him and is still pretending like he doesn’t exist. I immediately noticed the new puppy is very vocal and barks pretty much anytime he isn’t getting attention from us or our older golden. Also growls and barks at himself in the mirror which we thought was funny at first. My parents have the puppies half brother who is about 14 weeks old. We visited them this weekend and introduced them and they got along great and played non stop. The only thing I noticed was that after a while of playing my puppy started to growl, and would bite the 14 week old if he would try and take his toy or play too hard. At one point he even growled at me for trying to pick up the toy he was playing with. (And im not taking about a cute little puppy growl, he sounded pretty mad/scary)..Anytime we tried to give them time to rest by distancing them for a little bit, he kept squirming to go back and play. Even when it was time to go in his crate after playing (and using the bathroom etc..), he would bark constantly and not settle down. Since the day I brought him home I’ve been working on preventing food aggression with him by petting him while eating and he’s been fine until after this week being around his sibling he started to growl at me when I would pet him while eating. When he’s alone or just with our 6 year old dog he does not act this way. I’ve never had two puppies play together so I’m wondering if this sounds like normal behavior for a puppy so young. If not, what should I do to prevent worsening of this in the future? Thanks! Here’s some pictures of them!