change in aggressive behavior

Question
Hi,

I have a 14 year old neutered corgi mix (Rommel) and a neutered 10 month old corgi (Angus).  These two have gotten along extremely well from the time we brought Angus into our home at the age of 10 weeks.  There has been no problem with aggressiveness with regard to food or attention. Angus went to puppy training class at PetSmart and gets along well with other animals, as does Rommel.  Both of them have been socialized.

Recently, Rommel has become aggressive towards Angus and of course the puppy reciprocates!  Angus now outweighs Rommel by about 8-10 pounds.  After about 2 growls, the fight begins and I ususally separate them by using a blanket to pull them apart or I pull from their back legs.  They don't quit easily and this morning I got my first bite.  I scream and scold them (rather than using "settle"), and then separate them in rooms.  One time I put Rommel in the crate, but he was going crazy trying to get at Angus through the crate.

I don't know what has caused this change in behavior.  It started gradually about 3 weeks ago and escalated when took them on vacation last week.  It got so bad that Rommel couldn't see Angus across the room without starting a fight.  We finally sent Rommel back home to my mother who had no problems with him and her 2 dogs.  It is getting so bad that occasionally, Angus will now start the fight before Rommel does.  

Any suggestions?

Answer
Hey,
When Angus became a junior dog, not a puppy, fights took place over the dog's dominance over eachother. To stop this, anytime the dogs fight or bark, close their mouth by putting your handsaround the muzzle untill they start to whine, or keep flicking them on the nose untill they stop fighting.
If the nose flicking and mouth-closing doesnt stop them from fighting, you will have to appoint a dominant dog over the other, usually the stronger dog. You do that by calling the dog first, petting him first, and feeding him first...
If a dog bites you, ALWAYS flick the nose or close it's mouth.
Good luck...