Dog's fighting

Hello,

Yesterday we started to foster a lovely small male dog, we also have another small male the same age. We let them meet on nutural territory, allow our dog to enter the house first etc but he keeps attacking the foster dog if someone gets stressed. He seems to just charge at him and we have to interfere. Today though, nothing happened and our dog just charged at him so we don't know what to do about this!

Thank you.

I am not understanding the emboldened text

My dog can tell when someone is stressed, and today my mum was cause there was a spider so my dog saw that as a reason to go for the foster dog, but he's done it for no reason at all as well

How did your dog vent his emotions before the foster dog?

What type of dog are they, is it the first foster you have introduced to your current dog, have you tried walking them together, if mine have a spat I find by the time I get back they have settled down again.

Before the dog came he would usually just bark a little. And they walk fine together, in the garden no problem at all, just when they are in the house.

This behaviour could have so many causes I suggest you ask a behaviourist to come. Use one that uses positive methods (no whisperers, or bark busters!).

I suggest you send the foster dog back to the rescue he came from, so they can find a more appropriative foster home for him.

this situation is not good for either dog,

you must contact the rescue where the foster came from as this is a very bad situation for both dogs.
Have you fostered before (is your dog used to other dogs in his home?)

In your place I'd just consider that my own dog did not like having another dog around at all and the 'fostered' dog would have to go back whence it came.

It's not as if you HAVE to keep them both and it doesn't sound ideal for either of them.