Dogs got into huge fight

My dogs got in to a huge fight yester day and I am trying to wrap my head around it and figure out what to do from here…
I have two large size female dogs. One is 8 years old the other 4.
I had Harley (the 8 year old) since she was 4 months old and Creedence (the 4 year old) since she was 3 Months old. They have been together for a long time.
They always got along fine. They play with each other and have only ever fought (over food) when we first brought Creedence home. They are both very sweet dogs and love people. Especially Creedence. They are terrific with my little son and love to cuddle with him.
We have been watching my father in laws dog for the past few days and I noticed ever since we started watching the other dog, Creedence is trying to be very dominant with Harley, humping her and jumping on her back.
Yesterday they got into a huge fight. I’m talking, biting, snarling, dragging each other, knocking things over, blood flying across my backyard and hitting the wall of my house. (something you would see on a wild life documentary on national geographic channel just to give you a visual) my father in laws dog was not involved at all, there was also no food involved that could have started the fight. My husband was not home and I was to scared to break up the fight. They stopped after about 10-15 minutes of this and I thought for sure that one of them would end up dead. My husband came home and went out there to check on them. Disaster! My younger dog Creedence had a few scratches and bites on her face but my older dog Harley looked even worse. Deep bite wounds in her legs, her gums and scratches on her throat. We had to take her to the vet because she would not stop bleeding. She seems to be in pain and can barely walk but according to the vet will be fine. (Thank god my father in law picked up his dog last night!)
My question is, could it be that they were trying to reestablish dominance and who is alpha dog? And what do I do from here? I am worried that they will do this again and my son will get knocked over or caught in the middle. I love my dogs but obviously my Son’s safety is our number one priority.
Any suggestions or experience anyone could share would be greatly appreciated!

Is your dad's dog a male?

What have they been like together since dad's dog went home?

No, dad in laws dog is a female chocolate lab puppy (I think about 1 year old) It happened yesterday evening and we have kept them separate over night. Creedence (the younger one) walked up to Harley this morning but just sniffed her and I pulled her away. Harley went to our vet this morning and is still there being treated. So they have been separated all day but will be back together tonight.

I've never left dogs to fight it out tbh it's asking for trouble. Neither dog should be in charge or control that's the job of the humans. Are the Bitches neutered or entire? The fact that they eventually stopped of their own accord is a good thing but once they've had one big bundle it may well happen again. You need to start establishing some rules so that when you shout enough or leave it they stop what they're doing.

they are all neutered and until yesterday we had rules established and they listened very well. It was like they turned into different dogs. There was no way I was going between them to try to break up the fight being home alone with a 17 moth old Kid but thanks for pointing out the fact that you would have not let that happen, that really helps my situation so much.

It's a really difficult situation you have there (but you already know that so that's not much help).

The reason I asked if your dad's dog was male is that that can bring competition into the mix even though the male does nothing to bring it about.

Whatever happened, obviously the dynamics were disrupted. You might be lucky and they will go back to how they were (it can happen), but equally they may carry this forward.

It's serious aggression and you have a young child there who may stray into the mix so the safest way to proceed is to bring in someone who is well versed with this type of case to oversee the re-introductions and assess carefully what is going on, ie a behaviourist (with experience)

In the meantime, very strict management and keeping them separate so that everyone is kept safe.

Was you expecting someone to pat you on the back and say well done? We can only advise on what you say and you didn't say they normally back off when told to, also are you prepared for one to end up dead if it happens again. You can take various measures, step up their training, keep full buckets of water by the back door even dogs that like water don't like a bucketful at once. No one suggested you should step between them either, although in the past I've picked one up and dumped it in the pond. You need a place of safety so that if it happens again you can get your child out of the way and then deal with the dogs.

It might not be what you wanted to here but I agree with Trouble. I wouldn't let them harm each other to the best of my abilities. That can be dangerous obviously. I've never let being the only adult in the house keep me from stopping a fight.

I agree with Trouble, I would not allow them to fight it out, specially bitches, there is a saying dogs fight for breeding rights bitches will fight for breathing rights, in other words they can and do fight to the death, this is not a scaremongering tactic, there are plenty of people who sadly have been in such situations.

Never ever let dogs fight it out, regardless of sex, but when bitches take a dislike to each other it can be for life, it might be a one off for you but from now on you cant trust them together, As Trouble has said, you need to teach these dogs when you say enough you mean it, you are going to have to look for triggers (to what sets them off) there will have been one, you just did not see it, if this happens again, do as suggested, get your child out of the way and use what ever means, buckets of water cold hose in the face, loud noise, what ever it takes to separate them, but you might have to come to terms with the fact, you will have to keep them apart for the rest of their lives or in extreme cases re home one, I would also not allow any other dog to come and visit , you need to keep a strict regime, and maybe allowing other dogs in the house upset their status with each other.

Same here, on the odd occasion a fight erupted, I dealt with it on my own because I was on my own, I also learnt the triggers that would inevitably set of my bitch and removed them all,