How do you deal with a dog fight?

So I am new to Rover. I've done a lot of dog boarding in the past and thought I'd hop onto here to make a little extra money, and I got my first request for this weekend. It was all very exciting. It was for 2 dogs from the same household.

Both are very large. At least 65+ lbs. I asked the owner about any behaviors I needed to know about. He told me one had a little food aggression, and I was like ok I can deal with that. I found out later that the other one protects his toys. I mentioned that to the owner and he was like oh yeah forgot to tell you about that. I was irked a bit, but shrugged it off because it wasn't too big of an issue then.

Well like 15 minutes later, we're all in the backyard (my two pups, a friend's pup I'm watching, and these two). They're all running around, and then dog 1 puts his paws on dog 2. Dog 2 turns around and just bites onto his brother. To clarify this dog fight is between the two dogs from the same household. And then of course the other three dogs are going crazy too and I'm yelling at them to stay back. It was chaos. Pure freaking chaos.

I'm 5'2" and did my best to break this up. I know sometimes if you grab and lift their hips the dog will let go. It lasted about 3 minutes and the dogs did end up separating. I got swiped at one point so I have a scratch and bruise on my arm. I put them in separate kennels, called the emergency hotline, and called the owner.

Overall, I'm just like what??? This is my first time and this happens??? Like is this setting the precedence for what to expect out of future boardings? I don't even know what to think.