Why Does My Dog’s Breath Smell Like Fish?

Why Does My Dog’s Breath Smell Like Fish

Wondering what that rotten fish smell is and pondering upon why does my dog’s breath smell like fish?

Should you be worried? Maybe a little.

In this article, you’ll find out:

  • 11 reasons why your dog’s breath smells like fish
  • 9 tips on how to get rid of your dog’s fishy breath
  • And a lot more…

Why Does My Dog’s Breath Smell Like Fish?


Your dog’s breath can smell like fish when his mouth is filled with too much bacteria from tartar caused by plaque buildup. Your dog’s breath smelling like fish can also mean kidney and liver failure. Then, excessive cleaning of his mouth alone won’t eliminate the fish odor, a visit to the vet will be required.

11 Reasons Why Does My Dog’s Breath Smell Like Fish?

It is important to identify why your dog’s breath smells like fish so that the problem can be eliminated by treating the root cause.

Here are 11 reasons why your dog’s breath could be smelling like fish.

1. Anal Gland Disease

Dogs have anal glands, also called anal sacs on either side of their anus. These glands are responsible for secreting a certain fluid that dogs use to help them mark territories and communicate with other dogs.

When your dog constantly licks their own butt or another dog’s butt, it can cause the secretions to cause a fishy breath in your dog’s mouth as the smell of these anal gland secretions lingers in his mouth.

There are two ways how anal sacs affect the odor of your dog and cause a fishy breath in him:

A. From Licking Other Dogs’ Butts

The secretions from the anal sacs of each dog give information about the dog to other dogs. Each dog has a unique smell and when your dog is sniffing at other dog’s butts, he is trying to get to know the other dog.

Butt sniffing is normal dog behavior. However, this behavior can sometimes end up causing a fish-like breath in your dog as the secretions from the anal gland linger in your dog’s mouth and nose.

B. From Licking Their Own Butt

The second reason is a more grave issue. The reason why your dog’s breath smells like fish could be that he is suffering from anal sacs disease, a term for several diseases that affect the anal gland of the dog. Anal sacs diseases are quite common in dogs.

Anal sac diseases include the inflammation or abscess of the dog’s anal glands leading to rupture of the same. As per the AKC research, smaller dog breeds are more susceptible to anal sac disease.

Your dog might constantly be licking his butt, a symptom of anal glands diseases. Thus, this constant licking can end up causing a fishy breath in your dog as the odor from the secretions stays.

As per PetMd, below are a few of the anal sac diseases symptoms.

  • Discharge from anal glands
  • Constant licking of the butt
  • Unusual smell
  • Difficulty in defecating
  • Excessive tail chasing

Also Read: The Best Dog Food For Anal Gland Issues

2. Poor Dental Hygiene/ Periodontal Disease  


Just like humans, dogs can also develop gum diseases if they do not practice proper dental hygiene. In the same way, not practicing a proper dental hygiene routine can lead to various dental diseases.

Over 80 percent of dogs will develop some form of dental disease, also known as peridontal disease by age of 3, says Dr. JoAnna Pendergrass, DVM.

Without regular oral hygiene, the rate of bacteria like Bacteroides fragilis will increase. These bacteria are found in dogs with periodontal diseases and gum diseases.

According to an article by Dr. McCalley, if you notice swelling in your dog’s gum, bad breath, or yellow build-up called tartar, certainly, it is an indication your dog is suffering from dental disease or periodontal disease.

If you notice any unusual symptom in your dog’s mouth accompanied by breath that smells like fish, visit a vet as soon as possible to help diagnose the exact problem.

3.  Food Caught In The Teeth

Who has not been annoyed by the adamant piece of food stuck between the teeth? Not only is it annoying, but it can also lead to bad breath.

The same goes for dogs. Food stuck between teeth can then lead to inflamed gums in your dog and if left untreated, he can even lose teeth. The bacteria that results from the food stuck between the dog’s teeth can end up causing serious dental diseases, which in turn can cause smell like fish in your dog’s mouth.

According to expert advice from Dr. Pendegrass, to avoid the occurrence of such a disease, it is important to practice proper dental care such as brushing your dog’s teeth as regularly as a few days a week.

4. Tooth Root Abscess

As per Dr.Lorraine Hiscox, another reason why dogs develop breath that smells like fish could be due to tooth root abscesses.

Dr. Hiscox explains that a tooth root abscess is a serious infection that forms around a tooth’s root. Bacteria enters the mouth through a damaged or injured tooth, which causes the infection.

There are mainly 2 ways tooth root abscess can happen:

  1. Chipped or fractured tooth

Tooth fractures in dogs are commonly caused by gnawing on hard objects like bone, cage bars, antlers, ice cubes, cow or pig hooves, or hard nylon toys.

Bacteria can get access to the core of the tooth if the protective tooth enamel is chipped. As a result, it exposes the underlying dentin or pulp, thereby causing an infection that lead to tooth root abscess.

  • Periodontal disease

Periodontal disease can potentially result in a tooth root abscess. The infection does not go down to the bone through the core of the tooth in this case; instead, it travels along the edge of the tooth through the supporting tissues that surround the root.

If you notice any of the symptoms mentioned below,consult a veterinarian for the diagnosis of a possible tooth abscess.

  • Fishy breath
  • Loose teeth
  • Broken tooth
  • Blood on your dog’s toys as a result of chewing on them
  • Chewing on one side of the mouth or is dropping food when eating

If these symptoms are not treated on time, it could result in more grave health conditions in your dog.

5. Oral Ulcerations


Oral ulceration, also known as chronic ulcerative paradental stomatitis (CUPS), is a mouth illness that produces painful ulcers on the gums and mucosal lining of the mouth.

If your dog suffers from painful oral ulcers, his mouth could be smelling like fish. PetMd suggests that the main reason this happens is due to the bacteria and plaque present in the mouth.

Some dogs are more susceptible to oral ulcerations such as the Maltese, cavalier king charles spaniels, cocker spaniels and Bouvier des Flandres. At the same time, extra care needs to be taken for these breeds of dogs to prevent the onset of this condition. 

There are various reasons why your dog could be suffering from oral ulcers and it is important to get your dog checked by the vet so that the root problem is solved. 

6. Oral Tumors

If your dog suffers from a breath that smells like fish, undoubtedly, there are chances that he is suffering from a cancerous or non-cancerous growth in his mouth.

Dr. Jan Bellows says that oral tumors are abnormal masses that grow in and around a dog’s mouth area.

Oral cancer makes up almost 6 to 7 percent of all canine cancers. The exact cause of oral tumors is unknown, however, periodontal diseases play an important role in facilitating oral tumors.

Large breeds such as Boxer Dogs, Chow Chows, German Shepherds, German Shorthaired Pointers, Golden Retrievers, Gordon Setters, Miniature Poodles, and Weimaraners appear to be more susceptible to oral cancer.

A vet can prescribe the appropriate treatment to help your dog with an oral tumor. So if you notice any of the below symptoms in your dog, take him to the vet as soon as possible.

  • Drooling too much
  • Fishy breath
  • Oral bleeding
  • Sores in the mouth
  • Difficulty to chew
  • Loose teeth
  • Missing teeth

It is important to practice proper oral hygiene for your dog so that such conditions can be limited to a certain extent.

7. Upset Stomach/ Acid Reflux


An upset stomach or acid reflux can cause your dog’s breath to smell like fish. Thus, an upset stomach can occur in your dog if:

  • He has eaten something he was not supposed to eat.
  • If he has a sensitive stomach
  • If there are certain food sensitivities your dog is dealing with

The AKC has compiled a useful list of human food that dogs can eat as well as they cannot eat. Almonds, chocolate, macadamia nuts, ice-cream etc are a few examples of foods that dogs should not eat.

Note the following symptoms that indicate your dog could be suffering from an upset stomach.

  1. Lethargy
  2. Decreased appetite
  3. Drinking less water
  4. Visible symptoms of discomfort and pain

If you feel your dog could be suffering from an upset stomach, visit a vet as soon as possible as they can advise you on how to help your dog out.

Also Read: Can You Feed Milk Bones To Your Dog?

8. Fishy Diet or Supplements

If your dog has a fishy breath and you are worried about it, think back to his meal times. Did you feed him a fish-based diet? Or dog food that has fish flavor? Then, you have absolutely nothing to worry about.

So, what types of food discourage bad breath?

A particular research suggests that when dogs are fed larger-sized kibble, that provides better teeth contact and dental chews can reduce the build-up of plaque. It can then reduce the chances of fishy breath in dogs.

If you feed your dog a fished based diet or omega fatty acid supplements, surely, your dog could have fishy breath. In this case, you have nothing to worry about and good oral hygiene will take care of that!

9. Diabetes  

Diabetes is an endocrine disorder that can affect your dog.

The prevalence of diabetes in dogs is estimated to be anywhere from 1 in 500 to 1 in 100 dogs, says Dr Allison O’Kell. 

According to PetMd, diabetes in dogs can be of two types: Type 1 and Type 2

Type 1 diabetes in dogs results in the dog’s body being unable to produce enough insulin levels to synthesis sugar levels.

Type 2 diabetes happens when the dog’s body is unable to react to normal levels of insulin.

Diabetes can result in high levels of sugar in the dog’s body. Bacteria that facilitate bad odor survives best in saliva with increased sugar levels, thus, causing a fishy odor in your dog’s mouth.

If your dog suffers from any of the following symptoms that could be an indication of diabetes, take him to the vet immediately.

  • Drinking water more frequently than usual
  • Urinating more than usual
  • Losing weight
  • Increased appetite
  • Breath that smells like fish

If left untreated, diabetes can prove fatal to your dog.

10. Kidney Problems  


Breath that smells like fish in dogs can be an indication of a more serious health condition such as kidney problems, for instance. Kidney problems are the blanket term for multiple disorders that can affect the kidney of a dog.

Kidneys are important when it comes to filtering out toxins from the blood and form urine.

According to Dr. Ernest Ward, DVM of VCA Animal Hospital, kidney problems happen when your dog’s kidneys cannot perform their regular function and cannot eliminate waste efficiently.

When the kidney stops functioning, it can result in high urea content in the blood which results in the dog’s breath smelling like dead fish.

If you see any of the below symptoms in your dog, then take him to the vet as soon as possible. Your dog could be suffering from kidney disease.

  1. Lethargy
  2. Fishy breath
  3. Lack of appetite
  4. Urinating too much
  5. Vomiting
  6. Weight loss
  7. Apparent signs of pain and discomfort
  8. Urine with traces of blood

According to PetMd resources, kidney problems can be congenital or can be caused due to other factors. However, proper treatment can ensure the affected dog a quality life.

11. Liver Disease  

The liver is important in your dog’s body because it helps with digestion and the removal of toxins from the body. When the liver does not function properly, it can lead to the build-up of toxins in the dog’s body resulting in a breath that smells like fish.

According to Dr. Jennifer Kvamme, DVM, if your dog suffers from any of the following problems, chances are he is suffering from a liver malfunction.

  • Jaundice
  • Weight loss
  • Vomiting
  • Diarrhea
  • Decreased appetite
  • Changes in stool
  • Changes in urination
  • Seizures
  • Personality changes

If you feel your dog is suffering from liver disease, consult a vet as soon as possible. Liver diseases, if left untreated can lead to the death of the dog.

9 Tips On How To Get Rid Of Your Dog’s Fishy Breath


Your dog suffering from fishy breath could be an indication of a serious health problem or poor dental hygiene.

Here are 9 tips you can follow to help your dog regain his fresh breath!

1. Professional Dental Cleaning

If your dog is suffering from dental problems that result in fishy breath, you should consider getting your dog’s teeth professionally cleaned.

A professional dental cleaning session includes a thorough examination of your dog’s teeth, as well as thorough cleaning and polishing of his teeth that helps to remove tartar and build-up that can cause periodontal diseases in your dog’s mouth.

2. Regular Teeth Brushing

Brushing your dog’s teeth regularly can help avoid buildup like tartar and plaque that can cause dental diseases.

It is recommended to brush your dogs’ teeth twice a day to avoid dental or periodontal diseases. However, if you are unable to brush your dogs’ teeth twice a day, try to brush them at least a few days (2 -3 days) a week to main good oral health as advised by Dr. Pendergrass.

It is necessary to make strict dental hygiene a part of your dog’s routine. Dental diseases in dogs can get severe and at the same time, result even in the loss of your dog’s teeth.

3. Use Enzymatic Toothpaste

Prevention is the best cure. Enzymatic toothpaste such as this vet formulated enzymatic toothpaste- Vet’s Best Enzymatic Dog Toothpaste can be used to brush your dog’s teeth and maintain a clean set of teeth.

Enzymatic toothpaste contains certain types of natural enzymes that fight bacteria causing build-up and inflammation.

Vet’s Best Enzymatic Dog Toothpaste | Teeth Cleaning and Fresh Breath Dental Care Gel | Vet Formulated | 3.5 Ounces

4. Small Breeds Need More Dental Care

Small breeds of dogs like chihuahuas are more susceptible to dental diseases and need constant and strict dental care.

These dogs need a strict dental care routine to prevent dental and periodontal diseases that might affect them.

5. Check For Anal Gland Disease

One of the major reasons why your dog smells like fish could be anal gland diseases. If you notice symptoms that might indicate anal gland disease, consult a vet as soon as possible to diagnose such diseases.

Such conditions should be treated as soon as possible so that it does not aggravate into a much serious problem.

6. Healthy Balanced Diet & Fresh Water

It is necessary to provide your dog with a healthy balanced diet to prevent upset stomach and also acid reflux that can be quite painful for your dog.

If your dog suffers from food sensitivity, it is necessary to plan his food around that.

Similarly, encourage your dog to drink water regularly to clean and freshen their mouth and breath. As advised by Pets WebMD, dogs require an ounce of fluids per pound of body weight per day. A 10-pound dog would need about a cup of clean water daily.

7. Changing A Fish Based Diet

If your dog’s food is predominantly fish-based and has lots of omega fatty acid supplements, it can cause a fishy breath in your dog.

Also, try switching your dog’s diet for a more balanced diet. Moreover, this not only ensures a fresh breath in your dog but it also ensures a healthy dog!

8. Plenty Of Dental Chews

Give your dog plenty of dental chews like Virbac CET Enzymatic Oral Hygiene Chews for Dogs that will help reduce the build-up in your dog’s mouths. It improves the overall health as well as the strength of your dogs’ teeth and gums, thus reducing the probability of periodontal and dental diseases in your dog’s mouth.

Virbac CET Enzymatic Oral Hygiene Chews for Dogs

9. Check for Any Other Diseases

If you do not see any visible reason why your dog has a bad fishy smell, hence, consider that he could be suffering from kidney diseases or liver problems. These problems are usually accompanied by other serious symptoms.

Furthermore, take your dog to a vet as soon as possible if you feel your dog is suffering from any health conditions. If left untreated, these diseases can end up being fatal for your dog.

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