We have a similar issue - Looking for help with aggression towards our new puppy - we have 2 Bs (one F, 1 M) - the male is a BRAT rescue and now 3yrs old and has become aggressive towards the Frenchie pup (14wks) - at first he was interested and tried to play with him but lately he has attacked him unprovoked - from non-interaction across a room to attack the pup. We do feed them separately and they sleep separately -