babysitting going badly Options

[bruisersgirl]

Im watching a 2year old mixed breed dog. Ever since Coki settled in shes been very snappy.she will start playing with my dog and all of the sudden start fighting him.She begs him to play then just growls and snaps when he does. Or like yesterday I took them to the beach they played for a hour then I chained them to a tree with water so they could cool off. they'd been there for maybe 3 minutes and she just snapped at him. They had plenty of space and water. Bruiser had done nothing cause he was sitting watching me. She bit hard enough to draw blood and since bruisers mostly a pit bull Im afraid he could seriously injure or kill Coki if he really got to fighting her. I dont know what causes her attacks,its not fighting for food or water. please help me on this Im stumped

[JMM]

The dogs were chained up which means fight vs. flight kicked in. She felt cornered and nailed him to keep him away.
I would keep the dogs separated unless they are unleashed in an open space. An ounce of prevention will go a long way.

[bruisersgirl]

thanks JMM but it just doesnt make since. there was plenty of space and they are used to being tied on the porch. She was relaxed before the attack and after it. More often than not they get along great then boom something sets her off. They eat at the same time in the same room with no problems at all, they train together and right now they're laying down asleep together. So what could they possibly be fighting over?

[JMM]

They are use to being tied to the porch. Together? After being riled up? Does the porch resemble the park? Dogs do not generalize. Being tied in one place that is non-exciting does not equate to being tied in another.
Without some really experience help watching what goes on there is not going to be a great answer for you. Since this is temporary, separation is the safest thing for you to do.