Get

In Your Inbox

Dogster is reader-supported. When you buy via links on our site, we may earn an affiliate commission at no cost to you. Learn more.

Why Does My Dog’s Breath Smell Like Fish? Vet-Reviewed Causes & Solutions

Share

Smelly Dog

We’ve all encountered some bad dog breath. While it’s considered common for your dog’s mouth to smell a little, if you notice a change in the smell, it can be a sign of illness or a problem with bad dental hygiene. In particular, if their breath smells of fish, this is often associated with problems including dental disease, kidney or liver problems, diabetes, or a poor diet.

Below, we look at some of the possible causes of fishy breath in dogs, along with other signs to look for and what actions you can take. We also look at some remedies and solutions that might help improve your dog’s breath.

Dogster divider_v2_NEW_MAY_24_

The 5 Causes of Fishy Breath

Dogs and minty-fresh breath usually aren’t mentioned in the same sentence, but that doesn’t mean it should be considered normal for a dog’s breath to smell so foul that you can’t stand to approach them. A fishy odor is a strong smell, and it is one that you wouldn’t generally expect from a dog’s mouth. Therefore, it is worth investigating. Here are some of the possible causes of this smell.

1. Poor Dental Hygiene

Your dog can’t brush their own teeth, so it’s very easy for accumulations of plaque and tartar to take over. Dental treats and other products can help, but they often work better when used in conjunction with a good tooth brushing schedule.

You should brush a dog’s teeth every day if possible, otherwise do the best you can but shoot for at least once a week. There are many different types of toothbrushes and doggy toothpaste available that are effective and safe. You will also need to take your dog to the vet to have their teeth and gums checked out every 6=12 months.

Signs of poor dental hygiene include staining of the teeth, damaged or missing teeth, and redness of the gums. If poor dental hygiene has led to dental problems, your dog might exhibit signs of pain and distress while eating.

If you do see signs of dental disease, take your dog to the vet and have them checked over. You should also start brushing regularly, and you may need to change their diet if your dog is struggling to eat the food you’re providing.


2. Dietary Issues

If you’ve recently changed your dog’s diet, this could be the cause of the bad smell. Your dog might be eating poop, either out of a litter tray, from the yard, or even while out on walks, if you’re not paying full attention. It could also be eating from the trash which might be causing the smell.

Ensure you buy a good quality food that provides all of the nutrients your dog requires. Try to keep them from eating things that they shouldn’t, including human food.

border collie dog licks nose after eating
Image Credit: kathrineva20, Shutterstock

3. Diabetes

Diabetes occurs when a dog’s body either doesn’t produce the insulin it needs or doesn’t respond properly to the insulin that is there. This can lead to high blood sugar levels and lack of available energy for the cells of the body.

Typical signs of diabetes include increased urination, increased thirst, and weight loss. The vet will take a blood test to check blood sugar levels, and if your dog is found to have diabetes it will likely need regular insulin injections.

As with diabetes in humans, lifestyle changes can help manage diabetes, and this may mean putting your dog on a diet, ensuring they get enough exercise, and avoiding the feeding of human food, even in small amounts. Your dog must be seen by a vet if you suspect diabetes is the cause of bad breath because left unmanaged, it can be fatal.


4. Kidney Problems

The kidneys remove toxins, regulate blood pressure, and help prevent water loss.

Signs of kidney problems include excessive drinking and larger volumes of urine, vomiting, not eating, and weight loss. There may be ulcers and sores in your dog’s mouth as well.

The vet will take blood tests and conduct a urinalysis to help determine whether a dog has kidney disease, and likely treatments include dietary management and medications.

sick-beagle-dog-lying-on-the-floor
Image Credit: Elena Loza, Shutterstock

5. Liver Disease

The liver is another essential organ. It deals with food digestion and the storage of vitamins and minerals. It also removes toxins. Liver disease can include a wide variety of signs from reduced energy to a loss of appetite. In extreme cases, your dog might have bloody diarrhea or vomit, a painful abdomen, and yellowing of the skin.

If you believe your dog is showing signs of liver disease, you should visit your vet where they will conduct blood and urine tests for diagnosis. Treatment of the condition with a specific diet or by incorporating supplements into your dog’s daily nutrition is often effective.

Dogster divider_v2_NEW_MAY_24_What to Do About It

Depending on the problem and its severity, there are some steps you might be able to take at home to help improve your dog’s breath and the underlying cause of the problem.

Consult a Vet

You should make an appointment to see your vet as soon as possible. They will conduct tests to determine the cause, and they can advise if a different diet might be the best solution.

If you need to speak with a vet but can't get to one, head over to PangoVet. It's our online service where you can talk to a vet online and get the advice you need for your dog — all at an affordable price!

PangoVet_Mention-in-Content Savings V1

Clean Teeth and Gums

If your dog is showing signs of dental disease, it isn’t too late to start brushing your pup’s teeth, but it’s best to start with a dental exam and professional cleaning first. This will help ensure that any severe problems are managed before you take over the maintenance of a healthy mouth.

Change Diet

If you’ve recently changed your dog’s diet, this might be the cause of bad breath. This is especially likely if the new food you are giving contains fish or fish-based ingredients. A lot of commercial dog food does contain fish because, as well as being a good source of protein, fish also provides omega fatty acids, and a host of other beneficial vitamins and minerals.

When changing a dog’s diet, you should do so gradually by introducing a small amount of the new food to their existing food and increasing the ratio of new food to old food over the course of a couple of weeks. This can help prevent diarrhea and other digestive problems.

dog eating in a food bowl
Image Credit: dmytro Zinkevych, Shutterstock

Feed Supplements

If your dog is lacking in any essential vitamins and minerals, you don’t necessarily have to change their diet to hit all the necessary levels. Dogs can benefit from supplements like people can, just be sure to talk to your vet first to make sure supplements are necessary and that you’re giving the right amounts.

Dogster divider_v2_NEW_MAY_24_Conclusion

Dogs aren’t known for having minty-fresh breath, but that doesn’t mean it should smell overly bad, either. Strong oral odors can be a sign of poor health, a bad diet, or dental disease.

Watch for other signs that your dog might be ill and consult a vet to help decide on the best course of action.


Featured Image Credit: UfaBizPhoto, Shutterstock

Want content like this delivered to you?

Sign Up For Our Newsletter

News, insights, expert advice, and everything dog

* By submitting, you agree to our Terms & Conditions and Privacy & Cookies Policy.




How useful was this post?

Click on a star to rate (you can leave written feedback after clicking submit)

Help us improve Dogster for pet parents!

Your feedback really matters.

What did you like about this post? Also how can we improve it?

Join the conversation

2 Responses

  1. My little dog eats and loves everything Salmon. She eats Fromm’s Salmon A La Veg for her main course and Zuke’s Mini Naturals Salmon Recipe treats. That’s why she has stinky fish breath!

Leave a Reply

You’re very welcome to leave a comment or question. Please know that all comments must meet our community guidelines, and your email address will NOT be published. Let’s have a positive and constructive conversation.


Talk With A Vet Online

Peace of mind,
anywhere, anytime

Affordable vet advice

The Crate Setup Most Dog Owners Get Wrong (And How To Fix It!)

Most people assume that if their dog hates the crate, the crate is the problem. So they try a bigger one, a different...

1,500 Beagles Rescued from Wisconsin Lab Farm – Here’s Where They’re Going

You may remember that a few weeks ago, we reported on a tense situation at Ridglan Farms, Wisconsin, a facility infamous for housing...

Dogster’s Weekly Photo Contest Winners: Window Watchers (May 11, 2026)

Every week our team gets the privilege of sorting through our readers photos to choose what dogs will win this weeks contest! See...

Can a Relationship Work When One Person Doesn’t Like Dogs? Tips & When to Walk Away

For dog owners, a partner who doesn’t like dogs isn’t a minor quirk to overlook. Dogs aren’t a hobby you can scale back...

More related

What and When Is Doggie Date Night 2026? Here’s How to Celebrate

Many pet owners would be surprised to find out that there is an official day for Doggie Date Night. This year’s Doggie Date...

Imo-Inu (American Eskimo and Shiba Inu Mix): Info, Pictures, Care & More

Have you seen an Imo-Inu? These dogs are not only cute but friendly, too. They have an infectious happy temperament and are pleasant...

National Cavalier King Charles Spaniel Day 2026: When It Is & Fun Facts

We all love our dogs, and many of us have a favorite breed. For lovers of the Cavalier King Charles Spaniel, there is...

Black Golden Retriever: Info, Pictures, Origin & History

Can Golden Retrievers be black? Many people believe that they only come in a simple shade of gold, hence the name. Black is...

Keep reading

9 Best Hypoallergenic Dog Foods in 2026 – Reviews & Top Picks

If your dog has a sensitive tummy or you think they could be suffering from food allergies, you may be searching for a hypoallergenic recipe that can help them. The term “hypoallergenic” literally means “less likely to cause an allergic...

yorkshire terrier eating dog food from metal bowl

11 Vet-Approved Kong Stuffing Ideas & Recipes for Puppies & Dogs

Check with your veterinarian before adding any new foods to your dog’s diet, particularly if your pet has any underlying health conditions or is on a special diet. The KONG is an amazing toy that has been a true gamechanger...

beige fawn husky with multi-colored blue eyes lies on the carpet and chews a red KONG toy

Hill’s Science Diet Puppy Food Review 2026: Recalls, Pros & Cons

Review Summary If you’ve got a growing pup, you know how important it is to give them the best fuel possible. Hill’s Science Diet puppy foods are a great choice because of the company’s research-backed approach to nutrition. With over...

Dogster_Hill’s Science Diet Puppy Food Review

Can Dogs Eat Guava? Vet-Verified Nutrition Facts & FAQ

While not every kind of fruit is suitable for dogs, some are safe to feed in moderation and can even offer a nutritional boost. Guava is a tropical fruit from the Myrtle family that grows on trees. Guava is a...

Can Dogs Eat Guava

Can Dog Food Cause Elevated Liver Enzymes? Vet Approved Info

Blood tests provide a great gauge of your dog’s overall internal health. If you’ve recently had blood testing done and are curious about your dog’s high liver enzymes, you should familiarize yourself with what they mean and what’s causing them....

Ginger dog eating

Wysong Dog Food Review 2026: Recalls, Pros & Cons

Review Summary Wysong is one of the most popular premium dog food brands on the market, producing a wide range of supplements and dog foods. The brand promotes its products as holistic and healthy, with the goal of replicating a...

Dogster_Wysong Dog Food Review

10 Best Dog Foods for Shih Poos in 2026 – Reviews & Top Picks

If you have a Shih Poo, you know all about little dog preferences and demands. All pup owners want the best for their pooch—big or small. But diet needs change depending on body structure—just like with humans. So, we have...

shih poo sitting on a grass

Victor vs Taste of the Wild Dog Food: 2026 Comparison, Pros & Cons

Victor and Taste of the Wild are two comprehensive dog food companies that offer a premium variety of excellent recipes. Similar to one another, both lines of food offer grain and grain-free high protein, fiber-rich, fat-dense recipes. These companies set...

Dogster_Dog Food Victor VS Taste of the Wild

Love Dogs? So Do We! Join the Dogster Community

Stay informed with expert pet care insights delivered straight to your inbox! Discover professional guidance on animal behavior, feeding tips, trusted product picks, and much more.




Sign up for the Dogster Email Newsletter