My niece just called me in tears. They just got a 12 week old labradoodle puppy and their 6 year old labradoodle lunged at the pup and really frightened her.
She will be joining DK, but asked me for advice immediately, and I am in turn asking you.
The puppy is hiding behind the sofa and I told her to have her husband take the older dog for a walk and to sit on the floor and coax the puppy to come to her. But: WHAT NEXT. Thanks.
Thanks to everyone for the great advise. I'm closing the discussion as I'm sure this problem will be solved very quickly.
Protect the puppy at all costs, some older dogs are just not well socialized- or they resent the puppy intruding on 'their territory'. I would put the puppy in it's crate in proximity of the older dog first, when the older dog is calm and does not react badly toward the puppy (i.e. growling or raised hackles, or ears back, praise the older dog and give it a treat) you want to make the idea of being close to the puppy a good experience, and one that the older dog will look forward to. If they can get the older dog to calm down when the puppy is crated, my next step would be introducing the two on neutral territory. Hold the puppy in your arms and have someone keep the older dog on a leash, let the older dog sniff the puppy but make sure the person with the leash can prevent the older dog from attacking the puppy. If that goes well, then I would put the puppy down and keep the older dog on it's leash and closely monitor what takes place. At no time should they scold or punish the older dog, that will only make things worse.
If none of this works, they need to hire a behaviorist, or at least an APDT or CPDT trainer to work with them in their home. Usually this occurs when the older dog is a male, particularly un-neutered. An older female is somewhat easier because their maternal instinct will frequently kick in and they will tolerate a great deal of puppy nonsense
also a good idea is to walk them side by side, separated (again somewhere neutral). once they can walk side by side with some space, bring them a little closer but always have a tight rein on the leash. we just met a friend of ours who had a really aggressive dominant dog meeting our happy go lucky doodle for the first time and it really helped to do that with them.