What you need to do Whenever there is an aggression issue
is that you assert YOURSELF as the alpha dog
Yes your older pup is showing signs that he doesn't like the newcomer
and why should he?
This is a threat to his attention ... that's why he jumps up now on people he never did before
What you CAN do
is get them together .... and play with them BOTH
Give HIM lots of love and attention AND treats whenever she's around
and he'll finally get it
.... hey, when this new puppy is a round I get good things
