Behavior Issues!

Question
Hi, Please note:
**I have a Male German Shepherd, 2 years old. NOT FIXED!
**I have a Male Pug. 4 years old. NOT FIXED
**I have a FEMALE PUG. Less then 1 year old. IS FIXED!
>>Here is the situation.
Before we brought home the NEW Female Pug, the Male Pug and the Male GS got along GREAT! I really mean....GREAT! They played with each other all of the time. Best Buddies to say the least!
**Now.....Since we brought home the new Female Pug and even after we had the female spayed, we have notice a GREAT increase of aggression from the GS.
**The Shepherd is VERY aggressive toward out Male pug. Several time during the day, we have to keep yelling at him and scalding him for showing his teeth, etc. towards the Male pug. We are worried that he is going to hurt/attack the Male pug.
**The GS is very friendly towards the Female pug!
**When (anyone) now comes to the door. The GS acts like he wants to bite them. Even if he knows who it is. It doesn't matter!
**WE are very concerned about this CHANGE in behavior!
**To the best of our knowledge, we know he isn't sick in any way. We know he doesn't have anything like lyme disease.
>>What do you think is going on here besides the fact that the Male GS is just trying to be the Alpha Dog here?
>>Do you think is we NOW got him fixed, if this would make any difference? Or is it too late for that?

Please help!
Any suggestions would truly be appreciated!
Thanks!!  

Answer
You have a female in the house now -- and the boys are fighting for her affection, or at least who gets to sit closes to her, who gets to stand next to her, etc.

You can live in harmony with a number of intact males and females, I do it every day.  The key is to let the GSD clearly understand that his behavior is unacceptable.  Every time he shows his teeth, growls, or displays other unacceptable behavior, he gets a time out.  

Five minutes, ten minutes, up to an hour, however long it takes for him to learn to play nice.  The best is to place him in a crate so he can see what his missing. Patience is the key here, you must be diligent in that EVERY SINGLE TIME he even curls his lip at the other male, he must be told "NO!" and placed away.

He'll soon get the hint and your peaceful home will be back to normal.

Good luck.