You need to be able to correct with something that gives you the power to restrain him as well. So first...management. Don't put anything out of high value that he might attack over. Second...start training. Put a toy out, he takes it, take it away from him. If you see he's going to attack. Correct him with something you can also stop him from attacking with...you'll never stop him with an ecollar, you need physical restraint. When he stops/calms down. Give him the toy as a reward. Do this over and over again until he realizes that there are other ways to get what he wants.
Is he food aggressive? If someone walks by his food bowl does he growl/attack? Can you take his food bowl away from him while he's eating? He just has resource guarding issues, things that can easily be worked on.
This is not dominance...its insecurity. It's not understanding that he's going to get the toy or food if he just does what YOU want rather than just goes for it. Dominant dogs don't always have to use force to get what they want.
We just got a second GSD and at around the same time were dog sitting a female great dane that my dog has known his whole life. We were easily able to feed all three in the same area. If my dog walked away from his bowl (tends to do so as he is used to being an only dog) and one of the females went towards it to finish up, he'd calmly walk over and just nudge them out of the way. By day 3, they just left his food alone and would just walk away if he was coming back near it. If he wanted to he could move them away from their bowls, which I corrected and he stopped doing. This was an 80 lbs GSD moving a 130 lbs great dane with out any violence or aggressive behavior.
Last edited by martemchik; 03-04-2014 at 02:05 PM.