Aggressive new dog.

[SteveInNOLA]

I adopted a terrier mix that was found on the streets from a shelter 6 months ago. I brought my other dog with me to the shelter to let them meet and see if he was a good fit for our family. When the dogs met the terrier showed no aggression (the dogs still get along fine). For the first month or so, when I walked the dogs they didn't bark or react to other dogs aggressively. Over the last few months the terrier goes totally nuts barking, growling, flipping around on his leash every single time he sees any other dog. When I take him to the dog park and let him roam off the leash he usually gets along just fine. I have been using only humane training techniques, but no matter how many times I discipline the dog (I try to catch him as soon as he starts to go into attack mode) he won't leave other dogs alone.
About to pay a trainer $250.00, but am afraid the little guy won't ever calm down.

Help!

[divegirl]

Hi, what's he like with water? The technique I use, which some may frown on is a to use a squirty water bottle aimed at the dogs face.
I have a rescue Great Dane and though he has always been nervous he started to attack whilst on the lead [was fine off of it] after being attacked by another dog. To train him out of it I would walk him where I knew there would be other dogs and if he so much a looked at another dog he would get squirted and a firm LEAVE IT command.
You have to be confident to do this though....Sam was always on a loose/slack lead and you must never stop walking either....so it goes like this...
Walk towards the other dog and the second he looks at the other dog, squirt, command and keep walking at a steady pace. Walk 10 paces put the dog into a sit and then treat. Then repeat and repeat and repeat!

Lisa x

[wildwood]

A dog's character changes when they settle in. In the shelter it probably was a submissive dog so would be allowed to exercise with others which kept it in check. Are you sure he has aggressive intends when he wants to get off the leash? With all due respect to divegirl, I would stick to positive reward training, especially with a rescued dog.

If he has been a street dog for a while, it will be hard to settle him in as a house dog, roaming in packs is what comes natural to dogs and the even the most submissive dog will become a pack animal on the 'street'.

If you're about to fork out $(?)250 then put your faith in the trainer for now. Doing your own thing without the trainers instructions can make the poor thing even more confused.