My old chihuahua is having a hard time adjusting to new puppy.

Question
I have a 12 yr old chihuahua.He has a phobia to slippery floors so I usually carry him to our couch to rest during the day.He has his own area in the living rm with his potty area,a carpet and his basket.We just got a new puppy and the little guy won't leave our chihuahua alone.He has been trying to jump on the couch or go over to our older dogs area.Our older dog is very snippy,how do I make this work for both of them without someone getting hurt?

Answer
Treat the older dog like the sofa cushion or other things the puppy shouldn't chew.  As soon as the puppy focuses on the older dog, give it a sharp ''Ah, ah, ah!'' and offer it a chew toy.  I a couple of weeks, we will be getting the fifth new puppy since old aster came to live with us at 10 years old 4 years ago.  She wants nothing to do with their sharp little teeth.  We support her wanting to be left alone.