Moka and Mylee have always been the best of friends and snuggled together. They are 7 and 5. Two months ago Mylee got sick and was at the vet's for 2 weeks. She's doing very well, gaining weight, but still appears fragile, and her personality has never really seemed the same. Since her return home the agression has been building. More and more moments of the posturing, and challenging stares, and now it has lead to full on attacks. Moka is generally the agressor, but last night Mylee clearly challenged Moka and before I could stop it they had ahold of each other's nose and wouldn't let go. It was as bad as it sounds.
Mylee took a bite to the leg (no blood or broken skin but she is limping) and my husband took a bite to the finger. Moka has a small tear on her lip. I'm scheduling an appointment for Moka to check her out, but I don't think they'll find anything. She is a picture of good health. It just feels like Moka is targeting Mylee because she is "weak." I wouldn't consider either of them dominant or alpha dogs. They both submit to me quite easily. I consider myself good at knowing dogs in general, behavior, training, etc., but this is waaaaay out of my league. I am devastated by this new development. Can anyone offer any advice? How do I deal with this.