Teaching Goliath To Be A Good Citizen
We have two male, neutered, GSDs. Kofy is a year and a half and Goliath (aka Goli) is 1 year. They are brothers, from separate litters, born in Guatemala. Goliath we rescued when he was four months old from the parking lot owners on our block who would tie him to a tree and leave him there all night. We spoke to the owners and volunteered to take care of him at nights until they figured out a better situation for Goli. It never happend, so we convinced them to let us adopt him. So he didn't become part of the family until he was 7 months old. During the days Goliath would spend in the parking lot with no real owner or anyone to set guidelines for him. Kofy has been with us since he was three months old and straight out of the litter – he's been part of the family since day one. Kofy listens and never strays too far from either one of us. He only barks when a dog takes his ball or comes near one of us.
The main problem we're having is with Goliath. Goli barks at everything and uses barking as his main form of communication. He barks at Kofy when we throw the ball and Kofy, being the dominant one, runs for it, gets it and brings it back. Any kind of game where the two are involved, Goli will bark. Goli barks at other dogs, especially when those dogs get near Kofy and Kofy doesn't give Goli attention. He especially barks a bigger dogs or dogs that get near Kofy or one of his owners. The barks are not play barks, they tend to be aggressive or anxiety, fear-driven. The only dogs Goli doesn't bark at are small dogs.
When Goli barks aggressively or uncontrollably we usually get in front of him and say "Ahhh!" or "Leave It" and/or try to distract him by throwing the ball or walking away from what he perceives as a potential threat. It sometimes works, but it doesn't feel consistent enough.
Both dogs get about 1 - 1.5 hours of exercise a day. One of us is always around during the day (home office hours) to feed them regularly, play with them during the day and do at least two long walks and/or ball throwing sessions and some games and tug of war with rope. They sleep inside the house, in their own crates and we both give them lots of love and attention and park time.
I don't get what we need to do with Goli to get him to understand that barking and aggression is unacceptable in certain contexts and that he needs to obey us when we tell him to stop.
Any advice would be greatly appreciated!