How to teach adult dog and new puppy to get along?

I am planing to bring a new puppy. I already have a dog (4 years old). He does not get along with any dogs. When ever my neighbor's dog come into our garden he is very aggressive . How can I make them get along ? My old dog is tied up most of the time in the garden. And i am planning to bring Indoor dog . So should i always keep them away from each other... or how can i train them to be together ?

Show your pussy to both.letem lick.

A few years ago I rescued a very dog aggressive pit bull, it was a very long process introducing her, as I already had a 2 year old male Jack Russell. I can give you some suggestions and actions that we took. It is always best to introduce the dogs on neutral ground, such as the park, or even a few houses down the road(if the dog doesn't roam free) that way your adult dog is not territorial over the area since it is new to both dogs. Don't forget this is a puppy, so make sure they are both on leashes and the adult dog is only close enough to smell the puppy, otherwise that could turn into a disaster!!! Another small step that helped a lot was walking them at the same time. My husband would walk my Pit and I would walk my Jack Russell at the park, but we would stay at least 5-6 feet apart(and kept the leashes very short). It is important to teach your adult dog that you are the leader! Make sure that you are calm and always try to introduce them when the puppy is calm! I know that is nearly impossible, but try your best! Maybe your adult dog will not be as aggressive towards a puppy and is only intimidated towards larger dogs. You didn't say what sex the puppy is, but regardless it is important that the adult dog is neutered so the aggression is not just hormone reaction. Please make sure that you are showing your adult dog the same amount of attention as before. This can be very important also. Make sure you pay close attention to your adult dogs behavior, this will determine whether he is anxious, fearful, or just aggressive. Just remember if he is highly aggressive this will be a long process and will take time. Remember to be patient!!!!! Cesar Millan, has a lot of great books that could help you better prepare for introducing the new puppy, usually your local library carry these. Something definitely worth reading!!!! GOOD LUCK