The fox woukd have to be putting your pet cat in imminent danger. Just having a hissing -vs. -- screeching contest across the back yard probably won't give you a green light to shoot. (I say that although I will shoot any coyote that sets foot on my property if I have a safe shot to do so without endangering any neighbors. As far as I'm concerned, just being on my property where I have pets and where my neighbors pets are welcome visitors mskee the yotes an imminent threat. At least in my mind. I'm not sure if all law-enforcement officers game wardens prosecutors and judges would agree with me. Which is why any coyote slaying gunshot would be quickly followed by 1--a rush to grab the carcass, wrap it up in a garbage bag 2--put it in my garage, and lock the door, and 3-- I go back in my house and go to bed, where I will *NOT* be answering the door if anybody knocks to inquire about that sound .