Why Does My Dog’s Breath Smell Like Fish

Dog breath isn’t exactly known for being minty fresh, but if your dog’s breath smells distinctly like fish, it’s a sign that something might be off. This strong, unpleasant smell can catch you off guard — especially if your dog hasn’t eaten anything fishy. The cause usually goes beyond simple bad breath and can signal a dental, digestive, or even gland-related issue.

The Anal Gland Connection

One of the most common and surprising reasons for fishy-smelling breath is a problem with your dog’s anal glands. These small sacs near your dog’s rear produce a strong-smelling fluid that normally gets released when your dog poos. If the glands become blocked, infected, or impacted, your dog may lick that area to soothe discomfort — transferring the fishy scent to their mouth in the process. It’s unpleasant, but not uncommon.

Dental Disease and Oral Hygiene

Poor dental hygiene is another major culprit. Plaque and tartar build-up, gum disease, or infected teeth can all cause foul-smelling breath. While it might not always smell fishy specifically, some types of bacteria in the mouth produce a strong, sour odour that can resemble the smell of rotting fish. If your dog hasn’t had a dental check-up in a while, this could be the root of the problem.

Diet and Digestive Upset

Sometimes the cause is what your dog eats. If your dog’s food contains fish or fish oil, that can linger on their breath longer than you’d expect. It’s also possible your dog’s digestive system is struggling to process certain ingredients, causing reflux or a change in the natural bacteria in their mouth and gut. This can result in unusual or overly strong-smelling breath.

Foreign Objects or Oral Injuries

Dogs are notorious for chewing on things they shouldn’t. A piece of food, bone, or a foreign object stuck in their teeth or gums can begin to rot and cause a very strong odour. Injuries or abscesses in the mouth can also release pus or infection, which smells particularly bad — and sometimes fishy.

Licking Behaviour and Cross-Contamination

Dogs use their mouths to explore the world. If they’ve been licking parts of their body that carry stronger odours, such as the genitals or anal area, that smell can transfer directly to their breath. This type of breath issue is usually short-term but can recur if the underlying cause — such as irritated glands or infections — isn’t resolved.

When to See a Vet

If your dog’s breath suddenly starts smelling like fish, or if the smell is persistent and gets worse, it’s worth booking a vet visit. Anal gland issues can become painful and lead to infections if left untreated. Dental problems, too, can escalate quickly and may affect your dog’s overall health. A proper diagnosis will help get to the root of the issue and stop the smell for good.

Summary

So, why does your dog’s breath smell like fish? It could be anal glands, poor dental health, diet, or something stuck in their mouth. While it might seem like a minor annoyance, strong fishy breath often signals a problem that needs attention. With proper care and treatment, your dog’s breath — and their overall comfort — can quickly improve.