Having a dog that can get aggressive with other dogs, I know exactly how you felt when Arthur attacked Charlie. The fact that he wouldn't let Charlie go tells me a lot. Although Dazzi will attack other dogs I can pull her off and afterwards she knows she was wrong and will not go after the other dog again. With Dazzi there is often no puncture wounds but just lots of growling, rolling around, etc.

I too think Arthur was "wired" wrong. You did the right thing. It would have only gotten worse and something or even someone would have been killed.

RIP Arthur.

Get well, Charlie!