I have had my male cat, Aryo for almost a year now. We got him when he was only three weeks old, and I've raised him along with my dog I've had for six years now. They get along alright, he seems to like her. We decided to adopt another dog in January, and she is as sweet as can be. She's showed no sign of agression, and when we first got her, we slowly introduced Aryo to Nina, as you're supposed to do. However, for some reason he loves to attack her. Her isn't afraid of her, as he will literally let her sniff his face, or sit near him, but when she isnt looking, or at random times for no reason, he will attack. He will scratch her, hiss, or just smack her for no reason. I am not sure what to do, because he wont stop. I've tried everything I can think of, but I don't think that he is happy in this house, and Nina is terrified. We can't keep living like this, what can I do to help him stop attacking her?