Im mortified while writing this but need some advice.
I had my dog out for a walk to a new area today. Hes quite reactive to other dogs (growling and pulling) as he's on his lead but once he gets to sniff them he's fine. Anyway, he was being his usual growling self, had sniffed a few dogs and was fine then went to another dog and just went for it. There was nothing at all that other dog did. Luckily he was on his lead and I pulled him back and told him off while apologising to the owners, other dog was fine as no contact made.
My dog is a small terrier and is a rescue so I dont know much of his past. He interacts with other family dogs and kids and is great but today I got really worried. How do I train him out of this? Do I get him a muzzle for walks?