How to stop my dogs from fighting with each other

Fighting between dogs who live together is a safety issue, not a dominance struggle to referee — start by separating them safely with doors, gates, or crates, and rule out pain or illness with a vet visit, since sudden fighting often has a medical trigger. From there, manage shared resources (food, toys, resting spots, and your attention) so competition is removed, and bring in a certified force-free behaviorist for anything beyond mild, infrequent squabbles.

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Step by step

Separate immediately after any fight using doors, gates, or crates, and keep the dogs apart while you figure out triggers and get professional input — don't let them 'work it out' on their own.
Book a vet check for both dogs — pain, illness, or hormonal changes are common causes of sudden-onset fighting between previously friendly housemates.
Manage shared resources: feed in separate spaces, pick up high-value chews and toys when unsupervised, and give each dog their own resting spot so there's nothing to compete over.
Watch for early tension — stiff bodies, hard stares, raised hackles, growling over a resource — and calmly separate before it escalates rather than waiting for an actual fight.
Reintroduce shared time gradually and only under calm, structured conditions once tension has settled, rewarding both dogs generously for relaxed behavior near each other.
For repeated or intense fights, work with a certified force-free trainer or veterinary behaviorist (look for CDBC, KPA, or IAABC credentials) — this is one of the situations where DIY troubleshooting can make things worse.

Frequently asked questions

Why did my dogs suddenly start fighting after getting along fine?

Common triggers include a new pain or illness, a hormonal change (like a heat cycle), a shift in the household (a new pet, baby, or move), or competition over a specific resource. A vet check plus a close look at what happens right before fights start usually points to the cause.

Should I let them 'sort it out' themselves?

No — letting dogs fight it out risks real injury and tends to make the relationship worse, not better. Separate calmly and safely every time, then work on the underlying cause with structured management.

Is it normal for littermates or closely bonded dogs to fight more as they mature?

Yes, it's common — many dogs raised together get along well as puppies but develop more conflict around social maturity (roughly 1–3 years old). This isn't a sign of a doomed relationship, but it usually needs deliberate management and training rather than assuming it will resolve on its own.