How to tell which dog started the fight?

So my dogs have recently started fighting, after six years for no reason. Nothing has changed in the household. Every fight the has occured no one has directly seen it start, and there was nothing to hear like growling and such. They break out gor no reason, like the most resent, someone turned their back to get a drink from the fridge and they went at it. Is there any physical ways I can tell whuch dog started the fight? Thankd

Unless you saw the fight start there's no way to know.You need to separate these dogs unless you're watching (without exception, even if you're just going to the fridge). If the fighting gets bad enough you could very well end up with a dead dog because you weren't there to break it up fast enough. If the fighting continues to get worse you may need to separate them permanently.If this is new and there are no obvious signs (one dog being rude can be enough) you need to get both to a vet to rule out any medical reasons for the sudden aggression.

More time to spend with your pet