How to handle possible dominance fight btwn an established ALD and a newly adopted

[Susan, Coby & Chloe]

I haven't been on this site in quite a some time as things have been busy and going well -- with our 2 year old mini ALD Coby, as well as our latest addition we're thrilled to have, another sweet 2 year old medium ALD we adopted through Aly Rodges, the same trainer who had trained Coby in CA and had gotten Chloe as a re-home. We had flown out to meet her in early Dec and were won over by her charming good nature and disposition; she joined us a little over two weeks ago and the integration had been going very well...up until yesterday when the two "girls" got into a heated fight so intense in our bedroom we needed to separate them - snarled teeth, growling, the whole bit - seemingly out of no where. Crate time was initiated and they have each been - if I could use the word remorseful I would but let's settle on subdued, ever since.  Just when we had started to leave them alone together we're a little apprehensive about doing so.  Has anyone encountered anything similar?  if so, any suggestions?

[Susan, Coby & Chloe]

I've also heard about a small blow horn device to break up any scuffle that might start - as seemed to happen again this morning when I was down on the floor playing with the two of them. That was "my bad" - I think it's too early to try for such interactive play. And good point about the spaying, Ginny.

I spoke to Aly, the trainer who has extensive experience with Labradoodles and all dogs, trained both of mine. She feels I likely relaxed my firmness and rules too much. I'm back to stricter enforcement

In the meantime I'm learning more from these responses and appreciate the help!

[Nancy, Ned, Clancy, and Charlie]

We had 3 dogs when we got our adult rescue.  Our  'alpha' dog was about eleven, our Springer Spaniel ( a gentle soul) was about six, Ned (our other doodle) was two, and the rescue (Clancy) was also two.  Our alpha dog put Clancy in his place with a 'look,' Ned showed himself to be second in command with a few snarls within 24 hours.   Gordie and Clancy took several months before I felt comfortable leaving them alone together - argument was  for 3rd and 4th positions in the pack!  They argued over toys and us. We picked up all toys that THEY valued.  We separated them when we were gone and corrected with temporary separation and banishment when they had an argument in front of us.  There was lots of snarling growling and 'contact' when they argued. Eventually they worked it out and they enjoyed each other's company.  Clancy mourned the most when our Springer died suddenly this past summer.