Sibling rivalry, I think! Or maybe one of the females is trying to establish her dominance over the other. Since neither one them give in, I believe they will continue on fighting. I never have multiple dogs so I haven't experienced this sort of thing. When my nephew's dog comes to visit, Capone and the visiting dog fought too over the toy and food. They seemed to fight for their belonging and their boundary with one another.

Have you done some research on this? I am sure you will be able to find some information to practice on.

Food, toys or small animals that catch their interest can be a source of conflict for highly energetic mutts. You're keeping two large dogs. Each one of them has an excess amount of energy. Since dogs are territorial, they consider food, toys and the animals they find as part of their territory. And usually they don't share this territory with their siblings and even those dogs they've grown up with.

The hose is a good start but you can avoid letting them eat or play too near each other so they do not have to fight. They're big dogs. When they fight it must be horrible to look at. When you take away those things that'll cause them to compete and exert dominance over the other, as aforementioned, they'd be more relaxed in each other's company.

I sense it's a dominance issue. Not only is it between the two dogs. It might have to do with you as well. My lone dog has these issues as well. I'm the Alpha and I dominate him all the time. But once there is another person that enters the room, he tries to control that person and becomes possessive. It could be a dominance to each other and they might be trying to prove something to you.

I sense dominance issues as well.

Our dogs are all jealous for my girlfriends attention. This issue is paramount to them; more so than food even. Mainly this is settled within the pack with each knowing their place. Except for two of them where neither will back down.

We keep those dogs separated, which is a burden on us, but also a burden on them. They both end up isolated for part of the day because we are not willing to risk one of them getting injured.

My two dogs fight all the time and it gets to be an annoyance. I try to break them up but they go right back at it. I am about ready to get rid of my pit bull for other reasons as well besides the fact I do not want her to hurt my boston terrier. I am sure that it is just play and they are trying to ascertain who is going to be the dominant one but it is still frustrating, so I understand how you must feel. I hope that they get their issues worked out and do not hurt each other.

Sometimes there is nothing that you can do about this, I have even heard some trainers tell me that you should go ahead and pet and compliment the dog that was the apparent "winner" of the confrontation because this settles the matter and establishes this dog as the dominant one. They are simply establishing a hierarchy inside the pack.

I don't really subscribe to that view, but I do believe that fights, once in a while, are inevitable, yet there are also levels of fights, that go from playfully fighting for a toy to 2 dogs that are going for the kill, you are going to notice the difference because the later case is pretty horrific. Usually, if a single droplet of blood is shed, is time to separate the dogs for good, that's usually the threshold.

I agree with what has been said it definitely seems like a dominance issue. They are both fighting to receive your attention first. Dogs are pack animals and have alpha male and female, after these there is a hierarchy until you reach the bottom, that is the beta male and female.
Looks like neither of them want to be the beta female.

Every dog owner should know this: https://www.wikihow.pet/Break-Up-a-Dog-Fight particularly if you own more than one. But, even if you don't since you never know what other dogs you may run into when taking your dog for a walk.