Why Does My Dog Smell Like Fish? The Possible Causes

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Eww GROSS! Why does my dog smell like fish?! As dog owners, we’re used to our dogs showing up with a range of weird and stinky smells that require immediate baths or breath freshening. But if your dog starts developing a pungent and distinctly fishy odor (especially if it doesn’t go away) this may be the first sign of potentially serious health issues.

All dogs have their own special fragrance, and as dog owners we’re kind of used to it. If your dog gets wet, rolls around in something weird outside, or eats something from the trash – chances are they might end up smelling a little worse than usual – and possibly a little fishy too.

But if you start to get strong whiffs of fish odor (bad enough to make you gag, and bad enough to smell from a distance!) this can be a cause for concern and might be a sign of deeper health complications for your pup.

Some of these problems are an easy fix – but other times fishy smells can be serious enough to warrant a trip to your vet to rule out infections, abscesses, blocked anal glands, or escalating dental issues.

Why does my dog smell like fish?

Dogs are delightfully stinky creatures. It’s part of their charm! And they usually don’t mind at all, it’s just us as pet owners that sometimes have problems with their smelly butts, feet, and breath.

But when you and your family are all gagging and asking “why does my dog smell like fish!” it’s time to do some further investigation. Strong fish smells aren’t normal (unless your dog has recently had a tasty fish snack) – so it’s time to figure out what’s going on with your pup.

Common reasons that your dog might smell like fish

The first step to unravel this stinky mystery is to find the source of your dog’s fish stench!

Brace yourself, and then give your dog a quick sniff from end to end to see if you can pinpoint where the smell is coming from.

Smelling your dog’s face and ears can help you discover if your dog has common conditions like yeasty ears or bad breath – both of which can give off fishy odors. Smell your pup’s paws too, as these are other areas of your dog that can get a little yeasty.

Also check if there’s any unusual discharge anywhere on your dog. If the area around your pup’s butt shows signs of swelling, redness, or leakage – combined with a gag-worthy fishy smell, it’s most likely that anal glands are causing the problem.

This simple, but somewhat unpleasant sniff-test can help you quickly narrow down the possible cause of your dog’s fishy fragrance. The joys of being a dog owner, right?!

Let’s take a look at some of the most common causes that your dog might smell like fish.

Bad breath

Dogs don’t have the greatest breath at the best of times, and that can mostly be due to the fact that they (or more precisely we, as pet owners) don’t brush their teeth every day. Think of how nasty your own breath can get if you forget to brush!

If your dog hasn’t eaten any fish (or fishy treats) recently, but their breath smells like l’eau de tuna – this may signal that there’s a problem with your dog’s health.

The following health problems can all leady to fishy breath:

  • Gastro problems
  • Food stuck in your dog’s teeth
  • Plaque and tartar buildup
  • Gingivitis
  • Periodontal disease
  • Kidney disease
  • Diabetes
  • Tumor

Periodontal disease can be particularly concerning, as it’s a progressive disease that can affect your dog’s entire body over time.

Periodontal disease

Bacteria in your dog’s gums can cause strong, fishy breath that nobody wants to be near. It can also be an early warning sign of progressive periodontal disease, which can be a serious problem for your pet.

What causes periodontal disease in dogs?

Leftover food stuck in your dog’s teeth and gums are the perfect places for bacteria to feast and multiply. This can cause your dog’s gums to get inflamed. If you notice your dog has reddened gums, this is a classic sign of gingivitis.

Your dog can also suffer from plaque buildup which can harden and cause your dog’s gums to separate from their teeth.

These progressive periodontal symptoms can cause tooth loss, plus a breakdown of tissue, loss of bone density, and a myriad of other serious, ongoing problems for your dog.

Small breeds are particularly prone to periodontal disease, as their mouths are smaller and their teeth are closer together – which gives bacteria more opportunity to thrive.

If you’re not paying much attention to your dog’s oral health, and their breath is starting to get a bit whiffy – now’s the time to start!

How to prevent periodontal disease in your dog

You should get your vet to regularly check and clean your dog’s teeth and gums so they can catch any problems early on.

It’s also a good idea to get into the habit of regularly brushing your pup’s teeth at home – at least once or twice a week.

Human toothpaste can have harmful ingredients for your dog, so always use approved toothpaste that has been specifically created for dogs. These toothpastes are safe, effective, and can help prevent expensive doggy dental problems further down the track.

Dental chew toys, and dental sticks are also helpful for keeping your dog’s teeth free of plaque and tartar build-up.

Bacteria growth in your dog’s mouth can also be controlled with special dental water additives. Just a drop in your dog’s water bowl can keep their mouth healthy and smelling like strawberries. Okay…maybe not quite 🙂

Here’s some product ideas to get your dog started on their way to better teeth and gum health:

Top selling dog-friendly toothpastes

Top selling dog dental chews

When to see your vet about your dog’s bad breath

As soon as you notice that your dog’s breath smells like fish, check their gums for signs of swelling or redness. It’s never too soon to see your vet if you suspect that your dog has teeth or gum problems – as these can turn into serious (and expensive) problems.

The vet may also notice broken teeth or abscesses in your dog’s mouth that may be a cause of fishy breath too. Your vet will recommend treatments to get your dog’s dental work back on track. These will vary depending on what the specific diagnosis is.

While you’re at the vet, they may also ask if your dog has any other symptoms apart from smelling like a sardine factory. If you’ve noticed that your dog has any of these additional symptoms, it’s important to tell your vet:

  • Vomiting
  • Weight loss
  • Lethargy

These can be signs of something that goes beyond dental problems, and your vet will start eliminating other possible causes of the fish smell.

Smelly urine

Your pup’s urine should smell a lot like your own. Which means it should not smell fishy!

Causes of stinky urine

Much like us, your dog can develop a yeast infection, or a urinary tract infection (UTI) which is both smelly and painful.

These symptoms might also include:

  • More frequent urination that normal
  • Pain and whimpering when your dog urinates
  • Blood in the urine

Smelly urine can also be a sign of kidney stones, bladder issues, prostate problems (in male dogs) and even cancer.

When to see the vet about your dog’s smelly urine

If your pup has pungent pee, take them to the vet as soon as possible for examination and treatment. If it’s a simple UTI, it can be treated quickly and easily with a short course of antibiotics.

If smelly wee is an ongoing problem, your vet may do further blood and urine tests, ultrasounds, or x-rays to get to the cause of your dog’s issues.

Gastrointestinal problems

If your dog is gassing up a storm in your house along with their fishy smell, it’s time to see your vet. Your dog may have developed a food allergy and need their diet adjusted.

It might be that your dog is having gastric reflux (GERD) which can also cause fish breath. This can include classic symptoms like:

  • Drooling (more than they usually do)
  • Gulping air
  • Regurgitating food


If you suspect your dog has gut problems or food allergies, consult your vet to investigate new dietary options that can help settle your dog’s stomach.

Ingredients such as beef, lamb, soy, fish, wheat, corn, and pork, can all be triggers that your dog is sensitive to. If your dog eats these and you notice the fishy smell is accompanied by loose stools or other new symptoms, your vet can advise how you can shift your dog gradually to a new diet plan.

Dog probiotics can also be a useful addition to your pet’s diet. These can help reset any microbial upsets in your dog’s gut that may be causing problems for them. Probiotics flood your dog’s belly with good, healthy bacteria, which pushes out any bad bacteria that may have taken hold in your dog’s abdomen. Probiotic brands that include insoluble fiber and prebiotics can give added benefits to your pup’s health.

Yeast infection

Having struggled for 10 years with my own dog’s delightful yeasty problems – I know for a fact that yeasts can be a constant battle. Yeasts love dark, damp places and thrive in places like your pet’s ears, between their legs, between their toes, and around the vulva of female dogs. Female dogs can also suffer from vaginitis which is caused by a buildup of yeasts.

Yeast typically causes fishy odors, so your vet will do a sniff test of your pup’s ears and paws to eliminate this common doggy problem.

Thankfully, yeasts are easily treated with antibiotics – but it’s best to catch them early before they become too much of a problem.

Anal gland disease

Does your dog’s butt smell like fish? Then it’s likely the anal glands are a prime suspect – especially if your dog is a small breed.

If you notice stinky excretions coming from your dog’s posterior after they go to the toilet, they may also be licking that area and transferring all those smells to their mouth. Yummy.

Anal gland disease isn’t glamorous. And it can be pretty darn stinky. So if you notice signs of this, get your pup to the vet as soon as possible. They can guide you through the treatment and give you tips on how to manage this problem at home.

What are anal glands?

Anal glands (or sacs) are located on each side of your dog’s anus. They produce secretions which are unique to your dog, and act as scent markers. These glands normally function properly in your dog, and you don’t really notice them at all. But they’re the reason why your dog loves smelling other dogs’ butts in the park!

If your dog is scared, it can sometimes express its anal sacs out of fright. Even though this isn’t nice – it’s totally normal. So this could be the cause of your fishy smell.

The anal glands only start to cause problems when they stop secreting properly. Usually the glands will empty when your dog passes a stool, but sometimes they don’t empty properly. The resulting blockage begins to cause discomfort for your dog, which makes him groom excessively to try and fix things.

If your dog is having pooping problems, or develops diarrhea, the anal sacs can then become infected, which results in even more issues for your pup. So it’s best to get a vet check if you notice your dog paying too much attention to his posterior.

“Anal gland disease” is used to refer to a bunch of common problems in dogs, which we’ll take a look at below.

why does my dog smell like fish

Common anal gland problems in dogs

Typically, anal gland problems occur in smaller dog breeds. If your dog is obese, constipated, has chronic loose stools, or has food allergies, they may also be at higher risk of anal gland issues.


These impactions are the result of your dog’s anal sacs not being emptied completely when your dog poops. Your dog should naturally express the anal secretions, but often this doesn’t happy. The fluid then builds up in the sacs and dries out, which causes the impaction.

If you touch your dog’s anal glands gently and notice that they’re hard to the touch, and causing pain for your pup – this can be a sign of impaction.

Anal gland impactions can be caused by sac abnormality, or your dog may have runny stools or diarrhea which don’t trigger the anal glands to secrete when they’re supposed to.

If your pup’s impaction remains untreated, it can become an abscess, which is even more serious.

Abscesses and infections

Infections and abscesses are both serious problems for your dog. And seriously expensive at the vet!

If left untreated, abscesses can also rupture, which is very painful for your dog. They often require surgery, along with medication and antibiotics afterwards.

Your vet will want to check up regularly on your pup after any surgery to ensure there aren’t any complications, and that the glands are functioning normally.


On the less common side of fishy-smelling anal glands are tumors. These can be cancerous and spread to other parts of your dog.

Your vet will do a biopsy to confirm their diagnosis – and then they will most likely recommend surgery to remove the tumor if that’s the cause of your dog’s fishy smells.

Symptoms of anal sac disease

Along with your dog smelling like fish, you might notice these symptoms. Always take a note and mention these problems to your vet when you go in to get your dog checked:

  • Licking or biting below their tail
  • Scooting along the floor on their butt
  • Whimpering while defecating
  • Blood in the stool
  • Pus in the stool
  • Discoloration around the rectum
  • Hard lumps around the rectum

When to see your vet about your dog’s anal sacs

When you first notice a whiff of fish coming from your dog – it’s best to call your vet. Your pup might simply need his glands emptied manually, which should quickly resolve the problem.

Your vet will give your dog a rectal exam, and express the glands. They might show you how to properly express your dog’s anal glands at home if needed – or you might need regular vet visits in the future to do this, and to make sure there aren’t any other problems. Manual expression can cause unnecessary swelling for your pup, so it’s advisable that this is done professionally.

If your dog has impacted anal glands, the veterinarian may decide it’s best to remove them completely to improve your pet’s quality of life.

The vet may also recommend dietary changes such as a different diet, more exercise, or increasing your dog’s fiber intake.

why does my dog smell like fish

How to keep your dog’s anal glands healthy

While many causes of anal gland disease can’t be prevented, there’s a few ways you can help your pup stay healthy:

  • Introduce more fiber into your dog’s diet
  • Exercise your dog regularly
  • Give your dog plenty of water
  • Check your dog regularly to ensure there’s no signs of infection or unusual secretions
  • Make sure your dog’s stools look normal
  • Prevent your dog from becoming overweight
  • Give your dogs probiotics for good gut health

Some pups will always struggle with anal sac issues. But you can always try to ease these problems going forward, look out for the symptoms, and treat any complications before they get too serious.

How to prevent your dog’s fishy smell

Now we’ve looked at all the most common causes and treatments for your fishy smelling pup, let’s take a look at some steps for prevention!

  • Bathe your dog regularly
  • Ensure your dog keeps a healthy weight
  • Practice good doggy dental hygiene
  • Keep your dog’s bowl full of clean, fresh water
  • Have regular vet check-ups
  • Groom and clip your dog regularly if they’re long-haired
  • Keep an eye on any unusual new or ongoing symptoms

Always consult your vet if you need advice on how to prevent your dog’s fishy smells once the cause has been properly diagnosed.

Helpful products to banish your dog’s stinky fish odors!

Prevention is always better than an expensive vet visit. So once your pup’s problems have been diagnosed and treated by a vet, you can look at ways to avoid future fishy incidences.

These are some products that pet owners have found helpful in keeping their dog’s mouth, feet, fur, and butts in top condition:

  • Grooming wipes
  • Gentle hypoallergenic shampoos
  • Probiotic powders
  • Dental mouthwash and breath freshener
  • Dental water additives
  • Specialized wipes for anal glands

Here’s our list of top recommended products to help prevent those unpleasant fishy smells:

In summary – why does my dog smell like fish?

If you’re asking yourself “why does my dog smell like fish” – we’ve hopefully given you a few good answers!

If it’s something as simple as your dog eating out of the trash or rolling around outside in something unpleasant, then a quick bath or paw cleansing should get your pet back to their normal doggy-smelling self again.

But when the fishy odors seem to be coming from your dog’s mouth or butt, or your dog is experiencing other unusual symptoms along with this new smell – it’s best to consult with your vet to check that there’s nothing more serious going on with your dog’s health.

Fishy smells can be key indicators of periodontal disease and anal sac disease – both of which can be serious issues for your pet. If you’re concerned that the cause might be one of these diseases, it’s best to get your pup looked at as soon as possible. The sooner these problems are diagnosed, the easier (and less expensive) it will be for you to treat them.

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BarkZine is a small team of devoted dog owners – so we understand what it’s like to be obsessed with your pup! We consult with veterinarians and dog behavior experts to bring you the best advice for your furry companions.

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BarkZine is a small team of devoted dog owners – so we understand what it’s like to be obsessed with your pup! We consult with veterinarians and dog behavior experts to bring you the best advice for your furry companions.