Based on my little experience and generally young age, don't take what I have to say too seriously . Basically, I think Gonzo's fear aggression is being reinforced unconciously. When he is kept on lead (or retained by you, i.e. you holding him back) and he is approached by a larger dog, his "fight or flight" mechanism jumps in. Naturally, with a larger, more aggressive dog coming at him and him being restrained, he's going to fight. When he does this and you tell the owner of the large dog to go away, Gonzy learns that this behavior worked, therefore rewarding his aggressive behavior. Also, you mentioned that for fear of hurting Gonzo, you haven't been going to the dog park any more (or as much). This lack of dog-dog socialization along with the "rewarding" bad behavior would make him more inclined to "fight" than to "flight", I think. Plus, you said that when he became scared of your friend's dog, he ran towards you- thus displaying his first choice of "flight". Then, when the dog would not give up, Gonzo began resorting to "fight", or growling.

Also, when you take Gonzo out and try to 'protect' him from other dogs, I think you'd probably tense up, grab his harness/leash, and pull Gonzo back. Let's face it, even though you know Gonzy is only acting out due to fear aggression, you don't want to deal with vet bills, apologies to you or the other dog owner, regret, guilt, etc. So to avoid that whole scenario, you pull Gonzo away and this reinforces the idea of fear. Remember when we saw that GINORMOUS chocolate Lab coming toward us? Gonzo started acting iffy and you pulled Gonzo away and between your legs. Of course, all of us were tense and anticipating the next movement, waiting with baited breath for the Lab to leave. Naturally, Gonzo, seeing you as Alpha (or....I hope so, LOL), is becoming even *more* scared now that AlphaMom is tense and scared. As in a wolf pack, Alpha decides how to act towards strangers, and Gonzo will look to you to decide how to act. Confidence is of the utmost importance. The simple remedy for this is to get a friend who has a large, dark-ish, TOTALLY dog friendly dog. Go to a comfortable, but not Gonzo's, territory and allow the two to meet. Just for safety precautions, you can throw two muzzles on the dogs. Then, with a *slightly stiff* leash (not taut, but not too slack), allow the two dogs to sniff at each other. Move as the dogs move so the leashes don't get tangled and praise and reward. (You probably already know this ).

SOOOO, after all that, my suggestion is to avoid any circumstances where Gonzo is onlead and the offensive dog is off lead. This spells trouble all over it, and I would avoid the off leash dog park. However, I encourage going down into a city area with lots of other leashed dogs and send lots of messages of confidence. As the Alpha, you know which dogs you like and trust. Like with Gissie, Gonzo LOVED her! Even though she was almost twice his size and fairly dark, he adored her. I bet part of the reasons why he felt no apprehension was because you'd met Giselle before and knew she would never hurt a fly (a rabbit, maybe, but not a fly LOL). You were showing signs of happiness, good excitement, and you were just plain comfortable and not tense. Gonzo, being the subordinate dog, knew better than to question your judgement and was completely okay with Seshy, Megan, Gis, and Miko. That, plus they weren't dog aggressive

Have you read this article, yet? http://www.bcrescue.org/fearaggression.html
It deals with BCs, in particular, so that might help. Good luck and give Gonzo many smooches for me! Gissie is sending lots of lub and kissies to him.