...We have a great dog park nearby where he could run around and play if he's good!
Are you talking about the Ocean County dog park? Although we used to take our one dog, Atka, there all the time before we got our 2nd dog, just bear in mind that the moderators at those parks will ban dogs and people (forever) if you strike out 3 times with bad behavior. There are strict rules at these parks (no food, no treats, no toys, pick up after your dog, always be mindful of him, etc.). It's a membership-only park, and you can get licenses and member cards right at the Toms River Mall at the County Connection "store" (so convenient since government hours don't coincide with people's free time!).
Like I mentioned, we used to go there quite a bit, until we kept on running into dogs who were a little too high energy and would get our dog wound up, only asking for trouble. The owners of these dogs weren't the most responsible, either, which compounded the problem. They were never really bad enough that they would have gotten warnings or suspensions by the moderator, but I was too uncomfortable with the possibility of a full blown attack when one of the lazier moderators was working - the kind who like to stay inside the hut and just watch TV and not pay attention to what was going on in the park. In addition, our 2nd dog has a liver problem that makes anesthesia pretty rough to tolerate for her, so we also didn't want to chance emergency surgery if she were to get attacked by a high-strung and frustrated dog whose only means of exercise was the dog park.
I'd think about some private classes with a trainer first to address any dog-dog issues so that you don't run the risk of being banned from a place that you could find enjoyable. Plus, a professional may be able to help you see if this is true dog-dog aggression, fear aggression, territory on a leash, or something else, and how to properly deal with whatever it is. Just a few of my thoughts on this....
