My dog doesn't like my new dog!?

I have a 2 year old german shepherd mix dog that I've had since a puppy. 2 days ago I got a 1 year old yellow lab. The GS is male and the lab is female. Both have been spade and neutered. They do not get along. My GS seems to be very jealous of the new dog. They don't fight all the time but they have had a number of snapping barking fights. They're pretty civil until it comes to playing fetch and their rawhide bones and stuff like that. They sniff each other but when they're heads get close together they snarl then the barking and snapping starts up and it sounds HORRIBLE! You think they'll ever get along? How long does it usually take? Would pet training help? Should I enroll BOTH of them in the training? My GS has always liked other dogs. He's played and wrestled with dogs before. But with the lab he seems to want nothing to do with her. I don't know what to do. Maybe it'll just take time. Any advice??