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15 Reasons Why Your Dog Suddenly Smells Like Fish + 17 Tips

Why Does My Dog Suddenly Smell Like Fish

Oh boy… that fishy smell! 

And there’s no rotten fish in the house. It’s coming from your dog…

Yes, your dog smells like fish. And carries that fishy odor from room to room.

But why? What’s causing it? 

How long will this continue?

Help’s here! The answers to these and many more questions lie in this article. 

Keep reading to discover:

  • 15 reasons why your dog suddenly smells like fish.
  • 17 actionable and practical tips when your dog smells like fish.
  • 9 dangers to look out for when your dog suddenly smells like fish.
  • And many more…

Why does my dog suddenly smell like fish?

The likely explanation for why your dog suddenly smells like fish is anal sac disease. It refers to impaction, infection, abscess, and tumors in the anal sacs. All of these lead to a fishy smell emanating from your dog’s rear end. If left untreated, your dog might need surgery.

People also ask:

15 surprising reasons why your dog suddenly smells like fish (when scared)

#1: Secretions from anal glands

If your dog smells like fish, the most likely reason is a secretion from anal sacs.

What are anal sacs?

Just inside and on either side of your dog’s anus are two small sacs. These contain sweat glands that produce a foul-smelling secretion. Dogs use these secretions to scent-mark.

Now, secretions are released with the poop when your dog takes a dump. Secretions contain chemical information about the dog.

That’s the reason why your dog is interested in another dog’s poop. 

But in instances when dogs happily meet, they get up close and personal. That is, by smelling each other’s butts.

The truth behind butt sniffing

What’s with butts? Why not smell the face? Or feet?

But the butt, really?

This brings us back to the secretions that anal sacs produce.

Did you know that each dog has a unique scent? So when dogs sniff each other’s butts, they’ll know if they’ve met each other before. 

The scent of secretions helps a dog get information about other dogs. 

They’ll know if the other dog is a friend or an enemy. A male or female. Aggressive or friendly.

Butt sniffing also helps dogs identify other dogs they haven’t seen in years. Perhaps your dogs got separated for a while. 

They only have to sniff each other’s butts. And through that, they get updated about each other’s lives. 

About the places they went to. The food they ate. What they did.

Amazing, right?

However, not all dogs welcome butt-sniffing. If a dog doesn’t want to give out information, they’ll simply sit down. 

Then they cover their rectal area with their tail.

Fun fact: Did you know that sniffing butts is a stress reliever for dogs? I guess this is one thing that will forever puzzle dog parents.

But, it’s another story when your dog smells fishy. Especially after being outside. 

Perhaps, when they pooped, some of the secretions ended up on their fur.

They could spread the smell to places where they sit.

#2: When dogs are scared

I have a friend whose dog, Oreo, had a near-accident experience.

They were walking home when Oreo was almost run over by a car. 

Back home, my friend noticed a fishy smell. She didn’t notice the smell just before they left the house.

By then my friend was already aware that dogs express their anal sacs when scared. That explains the terrible smell Oreo had.

And it’s perfectly normal.

There are also other instances when dogs express their anal sacs. Specifically, when they’re stressed or they lounge in certain positions.

#3: Anal sac disease

One reason why your dog smells like fish could be anal sac disease.

Anal sac disease is a blanket term for problems involving the anal sacs. It includes impactions, anal sac tumors, and infections and abscesses.

Let me discuss them one by one.


Impaction occurs when secretions are not completely expressed. Some remaining fluid in the sacs dry up and this causes impaction.

This is very painful for a dog.

There are several reasons why this happens. First, there’s an abnormality in your dog’s anal sacs. 

Second, your dog has a soft stool. As a result, the anal sacs can’t be expressed properly when your dog poops.

Anal sac tumors

Anal sac tumors prevent your dog from completely expressing their anal sacs. This leads to firm and enlarged anal glands.

Abscesses and infections

A dog’s anal sacs can get infected. Without treatment, it could lead to an abscess.

Abscessed anal sacs are painful. If not treated, your dog might need surgery.

Symptoms of anal sac disease

Your dog smelling like fish is the first indicator of an anal sac disease. Look for other symptoms such as:

  • Difficulty pooping
  • Scooting on the floor
  • Blood or pus on poop
  • Biting or licking at the anus
  • A hard lump near the rectum

Risk factors

Some dogs are more prone to anal sac problems. Including the following:

  • Obese dogs
  • Small dog breeds
  • Dogs with skin mites
  • Dogs with hypothyroidism
  • Dogs with environmental allergies

#4: Dental diseases

Dog Breath Smells Like Fish

If not from your dog’s butt, their fishy smell could be from the mouth. 

In such cases, your dog’s breath smells like fish due to dental diseases.

Dental diseases include:

  • Gingivitis
  • Tartar, plaque, and calculus
  • Abscesses and infections in the mouth

Infection or inflammation surrounding the teeth is an indication of periodontal disease. 

The bad smell is due to the sulfur compounds in the bacteria.

Note: Check your dog’s mouth. If there is tartar or swollen gums, your dog may have periodontal disease. Tartar is a yellow or brown material on your dog’s teeth. 

Also, broken teeth may lead to a fish-smelling breath.

#5: Acid reflux

A dog suffering from acid reflux may have a fishy-smelling breath.

Acid reflux is also called gastroesophageal reflux or GERD.

A dog parent shares online about her Pomeranian. She said that her dog had a very sensitive stomach. Not to mention her breath smelled like a dead fish.

She took her dog to the vet for a check up. There was nothing wrong with the dog’s teeth, the vet found out. But it was probably due to acid reflux.

After the dog was given medication, the fishy breath disappeared.

#6: Eating animal poop

If your puppy smells like fish, they probably ate animal poop. 

Dogs are curious creatures. And puppies… Well, they may be more curious.

They love to explore their surroundings. Get a taste of the things they shouldn’t chew or eat.

And maybe even eat poop!

They may eat their own poop. Or your cat’s poop or other dogs’ poop.

This poop-eating behavior is called coprophagia.

This is disgusting to humans. But this is actually normal for dogs and puppies. Again, one of the things that will forever puzzle humans.

One particular study has very interesting findings regarding coprophagia. 

The researchers carried out two web-based surveys. One had 1552 returns and the other had 1475.

Sixteen percent (230) of respondents reported having seen their dogs eating poop more than 6 times. Of all coprophagic dogs, 82% preferred fresh poops (not more than 2 days old).

Also, the findings showed that of coprophagic dogs, 75.1% were over 4 years of age. Only 1.7% were less than one year of age.

Diet also did not affect coprophagia. Kibble was the main diet for 82.3% of poop eaters and 78.3% of non-poop eaters.

#7: Fish-based diet

A fish-based diet may be responsible for why your puppy smells like fish.

You have probably fed them fish. Or their kibble has fish flavor. You’ll smell fish from your dog’s breath if they belch.

There are also healthy fish-based supplements such as fish oil. The smell of fish on your dog might linger for a while.

If your dog smells like fish due to diet, there’s nothing to worry about.

#8: Vaginitis

Though it is rare in dogs, this disease can lead to a fishy smell.

Vaginitis affects dogs just before puberty or in the adult stage. However, it is more common in puppies.

The following factors could lead to vaginitis:

  • Cancer
  • Viral infections
  • Bacterial infections
  • Vaginal foreign bodies

According to this article, vaginitis could lead to uterine infections, subfertility, or infertility. Particularly if left untreated.

The most common symptoms include:

  • Inflammation
  • Licking the area
  • Vaginal discharge
  • Frequent urination
  • Attracting the males even if not in heat

#9: Pyometra

Pyometra could be responsible for why your female dog smells like fish.

Pyometra is an infection of the uterus. It is common in intact female dogs.

It is classified as close or open. In the open cervix, there is a discharge of pus. Pus usually contains blood. 

The closed cervix, on the other hand, has no discharge. But the distended uterus leads to abdominal enlargement.

Some dogs in heat go through hormonal changes. And this puts them at risk of infection in the womb.

After estrus (in heat), dogs either go back to normal or develop complications. This is more likely to happen 4 to 6 weeks after estrus.

But even after estrus, the progesterone level is high. This is to prepare the dog for pregnancy.

If no pregnancy occurs, the lining of the uterus continues to thicken. As such, cysts can occur in the uterus.

This leads to an infection where the womb is filled with pus. Your dog will experience vaginal discharge with a greenish tinge. And it smells like fish.

This study looked into several cases of female dogs with pyometra. One hundred eleven female dogs with pyometra were observed.

Of 111, 5% (72) had open cervix. Whereas 35% (39) had a closed cervix.

The findings include the following:

  • 21 dogs with open cervix had moderately or severely depressed physical condition
  • 22 dogs with closed cervix had moderately or severely depressed physical condition

Also, 41 with open cervix had mildly depressed physical condition. Whereas 16 dogs with closed cervix had the same condition.

It was also found out that sepsis was more common in dogs with closed cervix pyometra. Sepsis is an individual’s response to an infection.

Pyometra is a very serious condition. It can lead to blood poisoning, kidney failure, or death.

Signs may be different for each dog. But the common ones are the following:

  • Lethargy
  • Vomiting
  • Poor appetite
  • Increased thirst and urination

#10: Infections of the uterus

Spayed female dogs may smell like fish due to infections of the uterus.

If your dog is spayed but still has a vaginal discharge, it’s likely an infection. 

#11: Urinary tract infection (UTI)

A UTI might leave a fishy smell on your dog’s urine.

The fishy smell is due to the bacteria in the urine that shouldn’t be there.

Rolling in fishy-smelling urine can also be the reason why your dog smells like fish.

#12: Yeast infection

A dog can be susceptible to different kinds of yeast infections. And these infections have a fishy smell.

Yeast infection can appear in the ears, on the skin, or feet. These areas are the perfect places for yeast to grow.

Yeast also loves growing around the eyes and around the vulva.

#13: Rolling in dead fish (and other disgusting stuff)

Dogs are serial offenders when it comes to rolling in disgusting stuff.

By disgusting, I mean cat poop, other dog’s poop, dead fish, and dead carcasses of other animals.

Just look at this pooch rolling in a dead fish. Que horror!

Why do they find this so much fun?

Patricia McConnell, an animal behaviorist, had some hypotheses. One is to disguise the dog’s own scent. Apparently, this works if they’re stalking prey.

Another hypothesis is to appear more attractive to other canines. It’s like showing the dogdom how they have a lot of dead things in their territory.

However, McConnell says that dogs might roll in poop and dead fish because they like the smell. And that they attract others by doing this behavior.

She likened it to humans spraying on perfume because they love the smell of it.

#14: Licking and biting

It’s horrible if your dog’s breath smells like fish.

But what if they don’t have a fish-based diet or periodontal disease?

The smell could come from biting and licking their bum.

Particularly if there are problems with your dog’s anal sacs. It’s going to cause them discomfort.

In the process, your dog might express their anal sacs. Some of the fluid might end up in their mouth.

#15: In heat

A dog in heat smells like fish. 

Apparently, male dogs are attracted to this smell. It tells them that a certain female dog is at peak fertility.

That’s why you might notice the neighborhood male dogs camping outside your gate.

Female dogs go in heat (estrus) up to twice a year. During this phase, they go through hormonal changes.

This results in unique odors. Many of which will go unnoticed to humans.

But some pet parents can detect the smell of females in heat. 

In fact, there’s this one dog parent who shared his experience on a forum.

He complained that his dog stank so bad he couldn’t stay in one room with his dog.

Thinking that his dog bled and slept on the blood, he gave her a bath. But it did nothing to get rid of the smell.

The pet parent also changed the dog’s food and even assumed it was gas he smelled. But he was convinced it was the smell of his dog in heat.

How to get rid of fishy smell from dogs?

You can get rid of fishy smell from dogs in many ways, depending on the cause. Dogs usually smell like fish due to problems in their anal sacs. Take them to the vet to get their anal sacs manually emptied. Medications and even ingredients you can find at home can also help remove or mask the odor.

Whatever the cause of that smell, you don’t have to suffer. 

Here I will show you a lot of ways you can deal with a fishy smell. 

17 tips when your dog smells like fish

#1: Manual expression of anal sacs

Dog Anal Glands Expression

Problems with anal sacs almost always make your dog smell like fish. The best course of action is to take them to the vet.

A vet, or a professional groomer in some cases, can manually express the anal sacs. This should resolve the fishy odor.

In some dogs, especially the small breeds, a regular expressing of anal sacs is needed.

Warning: Manual expressing the anal sacs is not recommended for all dogs. This might lead to inflammation and scar tissue.

A dog only needs manual expression if their anal sacs are not emptying naturally.

Similarly, dogs with underlying conditions need to be checked by a vet. The vet might prescribe antibiotics or perform surgery when needed.

#2: Higher fiber diet

The size or volume of a dog’s stool is very important.

How so? It has a lot to do with keeping the anal sacs working fine.

With watery poop, there’s no pressure on the anal sacs. Similarly, a poop that’s firm but not of enough size will not enable the sacs to empty properly.

One solution would be to give your dog more fiber in their diet. This leads to a healthy bowel movement.

This is exactly what was recommended for a dog brought to a vet clinic in Iraq. The case of this particular dog was discussed in this case report. The dog showed signs of having anal sac disease.

Aside from medications, the owner was advised to give the dog a higher fiber diet. This is because the dog was having digestive issues.

#3: Medications and treatments

For infected and abscessed anal sacs, get medications or treatments.

The vet will clean the dog’s anal sacs with antiseptics. Depending on the situation, they might prescribe antibiotics. Or a hot compress to the affected area.

Once your dog is healed, they will stop licking and biting at their rear end. Consequently, the bad breath from the secretions will be gone.

Medications will also be needed for certain issues such as UTI and other infections. Consult with a vet for the best course of action to solve the stinky smell.

#4: Surgery

Should infection and abscesses remain untreated, it could get worse. 

Until surgery is the only option. Because there are instances when treatment is not enough.

During surgery, the vet may remove one anal sac or both. Don’t worry as this won’t affect your dog’s quality of life.

#5: Regular exercise

Exercise is a dog’s reliable partner in keeping healthy anal sacs.

It promotes better digestion. It also reduces a dog’s chances of developing a disease. 

And, if dogs are healthy, there’s be no need for manual expressing of anal sacs.

Note: Keep an eye on your dog’s weight to avoid obesity. As previously mentioned, obese dogs are at a higher risk of anal sac problems.

#6: Hydration

Hydration is one of the keys to having regular and healthy stools.

So provide your dog with plenty of clean, fresh water. 

Place bowls of clean water strategically around the house. It makes it easier for your dog to drink, even when not thirsty.

#7: Enzymatic toothpaste

Neglecting your dog’s teeth will find you in a sea of troubles.

A periodontal disease might not be apparent right away. However, it will eventually creep up on your dog.

Before it happens, regularly brush your dog’s teeth. It goes a long way in preventing gingivitis, plaque, and calculus.

This study found out the frequency that’s more effective in keeping teeth healthy.

The dogs in the study were divided into 4 groups:

  • 1st group was to brush daily. 
  • 2nd group was to brush every other day.
  • 3rd group was to brush weekly.
  • And the last group was to brush every other week.

At the end of the 28-day period, the findings were in. Brushing daily and every other day showed improved results.

But, it’s not just the regular routine of brushing teeth that’s important. What toothpaste to use is also important.

When brushing your dog’s teeth, use an enzymatic toothpaste. This is a special kind of toothpaste that has enzymes to fight bacteria.

The fewer bacteria, the less chance of tartar and plaque buildup. Plus, it will keep a dog’s breath as fresh as flowers.

Note: Enzymatic toothpaste doesn’t need rinsing. It is also safe to swallow.

Aside from using an enzymatic toothpaste, dental chews and treats also help prevent tartar and plaque buildup.

#8: Changing a fish-based diet

If you don’t like your dog’s breath smelling like fish, consider switching to another dog food.

You can switch to other flavors that won’t lead to your dog’s fishy breath.

But this is not to say that fish-based diets are not healthy. In fact, your dog can benefit from omega 3 and 6, which support healthy cell growth. 

Also, there might be cases where dogs are allergic to animal protein. And where fish-based diets are more suitable.

#9: Clean up after animals’ poop

The importance of prompt poop disposal cannot be stressed enough.

Of course, you don’t want your dog’s breath smelling like fish from eating poop. But it’s also important that dogs don’t pick up parasites and diseases from poop.

What’s more. Dogs carry parasites that can infect people. Children, in particular, are at high risk because they play in the dirt.

Other dogs are affected, too. Particularly the coprophagic ones. 

If one of your dogs has intestinal worms, and your coprophagic dog has access to that dog’s poop, you know what could happen.

#10: Distraction from rolling in dead animals

Don’t let your dog roll in that dead fish!

In her book, emergency critical care specialist Justine Lee shares a few helpful tips. She says that when her dog is about to roll in a dead animal, she calls him to her.

This is a form of distraction to keep your dog’s attention from the dead fish. If you have treats with you, use one to lure your dog toward you. 

Another thing Lee does is say a firm “No!” when her dog is about to roll. Then calls him immediately back to her.

“Leave it!” is also another handy command to distract your dog.

#11: Quick bath

Sometimes it takes only a quick bath to make your dog smell fresh.

There are many fragrant shampoos you can avail of from pet stores. Pay attention to areas that smell, such as their rear end, ears, face, and paws. 

Also, make sure the ears and paws are free from yeast infection. 

You can also use waterless shampoo if you don’t want to give your dog a full bath.

Here’s a video of a dog parent using waterless shampoo. Her dog had decided to roll in fresh cat poop.

#12: Deodorizing shampoo

Sometimes, an ordinary shampoo doesn’t do the work. Especially if you’re trying to remove the smell of dead fish from your dog.

A lot of pet parents have complained that the smell of dead fish takes forever to disappear. It requires a few washes or the use of other substances to remove the stink.

In such cases, use a deodorizing shampoo. Go for natural products that are safe for your pets.


If without a deodorizing shampoo, you can make your own solution.

Here are what you need:

  • 79ml (⅓ cup) glycerin
  • 240ml (1 cup) white vinegar
  • 946ml (1 quart) warm water
  • 240ml (1 cup) lemon-scented dish detergent

Mix these ingredients in a plastic container. Use like you would a shampoo. Then rinse.

#13: Vinegar

If the deodorizing shampoo doesn’t work, try vinegar. It is non-toxic.

Mix one part vinegar with 3 parts water and use it to rinse your dog. Or spray the mixture on the stinky coat and let it air dry.

Don’t worry. The smell of vinegar will dissipate.

Use vinegar, specifically apple cider vinegar, to clean a dog’s ears. This helps lessen the chance of infections.

Aside from that, it also helps prevent yeast infection on dogs’ paws.

Vinegar can also help in digestion. According to PetMD, vinegar helps a dog digest their food better. 

Add one teaspoon vinegar per quart of drinking water.

Note: Your dog might not like the taste of vinegar in their water at first. So be sure to place another bowl of water. This is to ensure that they remain hydrated.

#14: Mouthwash

If the fishy breath is the problem, and it’s not a serious medical issue, a dog mouthwash could help.

This might have you thinking, “How on earth can I make my dog use a mouthwash?”

Don’t worry. A dog doesn’t have to gargle mouthwash as humans do. 

Just soak a cotton ball or a clean washcloth with mouthwash. Then apply it directly to the gums and teeth.

Is mouthwash safe for dogs? Yes! It is made dog-safe, so it’s okay if dogs ingest it.

But if your dog hates getting their gums and teeth touched, you’ve got another alternative. The water additive type. Simply add it to your dog’s drinking water. 

Note: Mouthwash is your best bet if your dog doesn’t allow you to brush their teeth. 

#15: Limit carbohydrate intake

For yeast infections, don’t feed your dog too many simple carbohydrates. 

During digestion, simple carbohydrates break down into sugars. And sugars feed the yeast.

Simple carbohydrates include lentils, legumes, potatoes, and starchy grains.

#16: Antacid

When your dog has acid reflux, you may notice the following symptoms:

  • Drooling
  • Lip licking
  • Gulping air
  • Regurgitation

A vet will usually prescribe antacid to control these symptoms.

#17: Chlorophyll

Having a female in heat can be challenging in some ways. You have to separate them from male dogs if you don’t intend them to breed.

And, of course, there’s the fishy smell.

Thankfully, there’s one product that could mask the smell. It’s chlorophyll.

Now I hear you saying, “What’s chlorophyll doing in an article about dogs?”

Chlorophyll is available in medical supply stores. It comes in liquid, powder, pills, or capsules.

This is usually taken by colostomy patients. However, many pet parents have found the effectiveness of chlorophyll in masking odors.

One pet parent shared how she used it for her female dogs. She poured a tablespoon of liquid chlorophyll into her dogs’ food. Twice a day.

She found it effective in masking the odor of being in heat.

Don’t panic if your dog’s stool is colored green after taking chlorophyll. This is normal.

Warning: Don’t leave a female in heat and a male dog together. Otherwise, you might end up with an unplanned litter. Also, don’t use chlorophyll when you intend to breed the dog. If chlorophyll masked the scent, the male may not be interested to breed.