I currently have two Labrador’s. One is 7 and one is 6. A few days ago we brought a new 8 week old puppy into the house (lab / rott mix). The 6 year old gets along with him fine but the older dog seems unsure. If there are outside in the yard, he will play with the puppy, but if we are inside and the dog is up on the couch and the puppy is on the floor he is very aggressive. He has never hurt the puppy but he has growled and shown teeth and one time just nipped at the puppy. Any suggestions?