Why Is My Dog’s Breath Fishy? (Solved & Explained!)

Dogs are a man’s best friend, but sometimes a man’s best friend has breath that can smell unpleasant, even fishy. You may ask yourself why your dog’s breath smells like fish when nothing in his or her diet contains the underwater creatures.

Fishy breath in dogs can be caused by a variety of things, a few that can be helped by you, the owner, and some that may need your vet’s attention. Simply changing up your pet’s diet or paying close attention to their oral health may help resolve the problem. However, if these simple changes are not working, it may be a sign that the issue is caused by a larger health concern and requires a trip to the vet. 

In this article, I’m going to explore each of the causes of stinky, fishy breath and the steps you can take to help resolve the issue.

Why Is My Dog’s Breath Fishy?

What causes stinky breath in dogs?

As mentioned above, there are a few different causes of fishy breath in dogs. The causes can range from simple to serious and include:

  • Gut issues
  • Plaque buildup
  • Eating waste or other smelly things
  • Kidney problems
  • Liver Disease
  • Diabetes

Each of these issues will require a different course of action to take care of that stinky breath and get your pet to a healthier place. Let’s explore each issue and how it can be handled.

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Gut Issues Could Be the Cause

Just like humans, dogs have a delicate microbiome that keeps their gut healthy. If this gets out of balance, it can cause your dog to be unable to digest food as well, leading to a whole host of health problems, including bad breath (nutrisourcepetfoods.com). Changing up your dog’s food to something more digestible can help to cure stinky breath.

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Adding food into their diet that contains probiotics can be a quick solution to improving your dog’s gut health. The good bacteria in the probiotics will help to cancel out the bad bacteria that may be causing the bad breath.

Your Dog’s Teeth May Have Plaque Build-Up

A dog’s oral health is often overlooked. However, your pet needs their teeth brushed and regular teeth cleanings, just like humans. If you’re not brushing your dog’s teeth, plaque can build up on the teeth and gum lines, turning into tartar that can cause an overabundance of bad bacteria. This bad bacteria in the mouth can lead to the development of halitosis, periodontal disease, or gingivitis which all can cause, you guessed it, bad breath.

If bad oral hygiene is the cause of your dog’s stinky breath, invest in a good pet toothbrush and toothpaste in a flavor that may be appealing to them, and begin brushing their teeth daily. Depending on how much plaque buildup your dog has, you may need to pay a visit to your vet for a more thorough cleaning to take care of the problem.

Is Your Dog Eating Something While You’re Not Looking?

Even the most well-behaved dogs can misbehave at times. If your dog has smelly fish breath, you may want to watch them more closely than usual for a while and see if they’re getting into something they shouldn’t.

If your dog gets into the waste, whatever is in, there will be on his or her breath! Be sure that all waste is well protected from nosy, curious dogs. Also, any products that you use in the kitchen, bathroom, or elsewhere must be out of reach of your pet. Sometimes dogs will eat first, ask questions later, and you don’t want to find that your favorite makeup product causes your dog’s bad breath!

Dogs cleaning themselves could also be a culprit for bad, fishy breath. Dogs have two anal glands that need to be “expressed” from time to time. When these glands are “expressed,” they can release a very strong fishy smell. If your dog then goes to clean his or herself with their tongue, the odor will be present in their mouth afterward.

Unfortunately, unless you catch them in the act, this one is hard to resolve. One way to help moderate this cause of bad, fishy breath is to be sure your dog gets their anal glands “expressed” when they visit the vet. This may help to regulate when they are released and prevent your dog from feeling the need to clean themselves.

The More Serious Causes of Bad Breath

If none of the above-mentioned causes seem to be the reason your dog’s breath is smelling a bit fishy, there may be more serious health concerns that need to be considered.

Diabetes, Kidney problems, or Liver disease can all produce bad breath side effects (forevervets.com). Diabetes causes sugar imbalances in your dog’s bloodstream, sometimes producing unpleasant-smelling breath. Alternatively, if your pet has developed Kidney issues or Liver disease, each of these ailments can cause extremely bad breath.

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If you suspect your dog may have one of these illnesses, it is important that you get them into your veterinarian for a full check-up. Your vet will be able to assess the situation around your dog’s health and whether the breath issue is an indicator that something more serious is happening with your pet’s health. If it is found that your dog has one of these illnesses, you and your vet can come up with a treatment plan to hopefully help your pet along the road to recovery.


If your dog is exhibiting bad, fishy-smelling breath, it may be time to take steps to figure out what could be causing the issue and what you can do to fix it. If you’re concerned that your dog’s breath may be a clue to a deeper health concern, it’s always best to work with your vet to find a real solution instead of trying to treat it at home. However, it will be a simple fix most of the time, and you and your dog will be on your way to a happy, smell-free environment!