Our two dogs have lived together for 6 months, since I moved in with DP with very little problem. They play together, eat together, curl up in the same bed.
Tonight, they have tried to kill each other. Serious fight, couldn't separate the, for a good 10 mins. Have been at emergency vets with both of them.
Big guy has big wound on chest, which they've just flushed out and a chunk out of the back of his front leg. Vet has stapled that.
Smaller girl has managed to bite her own face and get her lip stuck inside. Big guy has inflicted a few grazes on her, but I think most of the damage on both of them came from her. I think she was the aggressor and he was mostly defending himself. I'm being objective, that's not just because he's my dog.
I'm devastated at the damage that these two have done to each other, blood all over outside and kitchen floor. I'm just so shocked and upset because I thought they were getting along ok. 
Vet bill £400 for tonight and will need more follow ups.
Do they learn from things like this? Both clearly feeling very poorly right now.