Is It Normal For Your Cat’s Breath to Smell Like Fish?

Does your furry friend have fishy-smelling breath? You lean in to give them a kiss and get a whiff of something fishy. This is common for cat owners and usually nothing to be too concerned about. But what causes that fishy cat breath? And when should it ring alarm bells?

In this article, we’ll discuss the common causes of fishy cat breath, when you need to call the vet, and tips to help freshen up your feline’s fishy mouth. Read on to get the scoop on what’s normal and what’s not when it comes to your cat’s stinky fish breath.

What Causes Fishy Cat Breath?

There are a few main culprits behind that fishy odor coming from kitty’s mouth. Here are some of the most common causes of fishy-smelling cat breath:

Eating Fish Flavored Food or Treats

One of the most obvious reasons your cat’s breath smells like fish is because they eat a lot of fish-flavored foods or treats. Fish flavors are very popular for cat foods and treats. So if your cat chows down on foods labeled tuna, salmon, seafood medley, or other fish flavors, it can make their breath take on a fishy smell.

The same goes for crunchy treats marketed as “fish” flavors. The fish oil coatings and fish ingredients can get stuck in your cat’s teeth and cause lingering odors.

So if you notice fishy breath after feeding fish-based foods, this is likely the culprit. Switching to a different protein or flavor may help curb the fishiness.

Dental Disease

One of the most common medical causes of fishy cat breath is dental disease. Conditions like gingivitis, periodontal disease, tooth decay, and mouth infections can all cause foul, fishy odors.

When plaque and tartar build up on the teeth, the gums become inflamed and pockets form where food particles and bacteria get trapped. This causes bad breath.

As dental infections worsen, abscesses in the mouth can develop with pus that smells fishy. Tooth decay exposes inner layers of the teeth to bacteria, also causing smelly buildup.

If the dental disease is severe enough, your cat may even have rotting teeth that give off a very foul, fishy odor.

Kidney Disease

Another common medical cause of fishy cat breath is kidney disease. The kidneys filter waste products from the bloodstream. When the kidneys aren’t functioning properly, these waste products can build up in the saliva and be expelled through the mouth.

This causes what’s often described as a urine or ammonia-like odor. In later stages of kidney disease, ulcers can form in the mouth which worsen bad breath.

Kidney disease often causes increased thirst and urination as well as weight loss, vomiting, diarrhea, and other symptoms. So fishy breath combined with any of these other warning signs points to potential kidney issues.


Uncontrolled diabetes is another disease that can lead to stinky breath in cats. When cats have diabetes, their bodies lose the ability to regulate blood sugar levels properly.

As a result, the body starts breaking down fat and protein stores for energy. This produces ketones as a byproduct. Ketones have a very distinct fishy, fruity, or acetone-like smell.

Cats may breathe out these ketones in their breath. So if your cat has symptoms like increased thirst, increased urination, weight loss, and fishy breath, diabetes may be the cause.

Gastrointestinal Issues

Certain gastrointestinal issues can also lead to fishy-smelling breath in cats. For example, inflammatory bowel disease and malabsorption disorders can cause digestion problems.

When food isn’t properly digested, the undigested contents can start to putrefy and ferment in the digestive tract. This releases smelly compounds like hydrogen sulfide gas which cats may belch up or breathe out, causing bad breath.


Bacterial, viral, fungal or parasitic infections anywhere in the body can also lead to foul breath.

Certain infections cause ulcerations in the mouth, releasing smelly byproducts. Upper respiratory infections can cause excess mucus in the throat and sinuses which breeds smelly bacteria. And infections in other organs can release foul-smelling compounds in the bloodstream that may be expelled through the breath.

So if your cat has fishy breath along with other symptoms like lethargy, fever, diarrhea, or discharge, an underlying infection could be to blame.

When to See the Vet About Fishy Cat Breath

Mild fishy breath on its own isn’t necessarily a major concern. But a very strong, foul fishy odor, or fishy breath along with other symptoms, warrants a vet visit to identify the underlying cause.

Here are some signs it’s time to take your cat to the vet:

  • The fishy odor is very strong and foul
  • You notice weight loss, lethargy, or other systemic symptoms
  • There are dental issues like red/swollen gums, oral ulcers, loose teeth
  • Increased thirst, urination, or other signs of kidney disease
  • Changes in appetite, vomiting, diarrhea
  • Fever, discharge, or other signs of infection

The vet will begin with a physical exam, looking in the mouth, feeling the abdomen, checking temperature, and assessing overall health. They may recommend:

  • Blood and urine tests: To check kidney function, blood sugar levels, signs of infection, and other indicators.
  • Dental exam: To inspect for dental disease, tooth decay, and oral infections causing bad breath.
  • Biopsy or cultures: To check for cancer, fungal/bacterial infections, and other problems.
  • Imaging: X-rays and ultrasound can check for dental issues, kidney/liver disease, diabetes, and masses.

Based on exam findings and test results, the vet will diagnose the underlying cause and prescribe appropriate treatment. This may include:

  • Dental cleanings and tooth extractions
  • Kidney medications and intravenous fluids
  • Antibiotics for infections
  • Insulin therapy for diabetes
  • Steroids or diet change for gastrointestinal disease
  • Probiotics for digestive health

So schedule a vet visit if your cat has persistent fishy breath along with other troubling symptoms. Getting the underlying condition treated will help freshen up their fishy breath.

Tips to Minimize Fishy Cat Breath

Here are some tips to help curb your cat’s fishy breath when the cause is mild:

Feed a High Quality Diet

A natural, high protein diet with limited fish ingredients can help minimize fishy odors. Look for foods featuring novel proteins like turkey, duck, venison, or rabbit rather than lots of fish.

Canned or raw food is ideal since the moisture helps clean the teeth. Avoid dry kibble, which is more likely to get stuck in teeth.

Brush Your Cat’s Teeth

Regular toothbrushing keeps plaque and tartar at bay. Use a soft bristle brush and cat-safe toothpaste. Brush in gentle circles concentrating on the outer surfaces. This freshens breath by removing bacteria.

It may take time for your cat to get used to brushing. Start slow with just a little each day. Reward with treats after!

Provide Plenty of Fresh Water

Staying hydrated dilutes odor-causing compounds in the saliva and flushes the mouth. Cats are prone to dehydration, so give ample fresh water daily. Consider adding an extra water bowl or cat drinking fountain.

Schedule Regular Vet Dental Cleanings

Even with home brushing, most cats need annual dental cleanings. The vet fully anesthetizes them and scales away all built-up tartar – much more effective than anything we can do at home! This keeps teeth and gums healthy and breath fresh.

Ask About Probiotics

Probiotics support digestive and immune system health. They may also freshen breath by crowding out bad bacteria in the mouth with beneficial microbes. Ask your vet about appropriate probiotic supplements.

Offer Chew Toys and Treats

Chewing scrapes away tartar while chewing gums or dental treats are designed to reduce plaque. Offer treats and toys made specifically to promote dental health.

Try Natural Remedies

Some people report success reducing kitty breath odor by adding small amounts of parsley, mint, dill, or green leafy veggies to their food or water. You can also try plain yogurt or apple cider vinegar. Just introduce new foods slowly.

See Your Vet Regularly

Routine wellness exams allow early detection and treatment of dental disease, kidney disease, diabetes, and other problems leading to bad breath. Your vet can also assess the need for professional cleanings.

With diligent home care and your vet’s help, you can get to the bottom of your cat’s fishy breath and get their mouth clean and fresh-smelling again!

Common Questions About Fishy Cat Breath

Here are answers to some frequently asked questions about smelly cat breath:

Is it normal for my cat’s breath to smell like fish?

A slight fishy odor is common and normal, especially if they eat a fish-based diet. But a very foul, strong fish smell can indicate dental disease, kidney disease, diabetes, or other medical problems needing treatment.

How can I make my cat’s breath smell better?

Try brushing their teeth, feeding high quality foods without fish, staying hydrated, scheduling vet dental cleanings, and using cat-safe breath fresheners. Treat any medical conditions causing bad breath.

Do cats’ mouths just naturally smell bad?

Cat mouths have a unique odor, but shouldn’t smell terribly foul. Bad breath indicates dental plaque, gum disease, rotting food stuck in teeth, or illnesses needing veterinary attention.

What home remedies freshen cat breath?

Some natural remedies thought to help with cat breath include:

  • Adding mint, parsley, dill or green leafy veggies to their food
  • Putting yogurt or apple cider vinegar in their water
  • Giving raw carrots or other crunchy veggies to chew
  • Brushing teeth with baking soda and water paste
  • Using water additives with chlorophyll

When should I take my cat to the vet for bad breath?

See your vet promptly if your cat has a very foul, strong fishy breath smell, especially if combined with signs like vomiting, diarrhea, dental issues, increased thirst/urination, or lethargy. These require medical treatment.


A slight fishy smell from your cat’s mouth is fairly common and not too concerning on its own. But a persistent foul, fishy odor, especially when paired with other symptoms, can indicate health problems needing veterinary attention.

Work to reduce fishy odors through dental care, diet changes, and other breath freshening tips. But also watch for other troubling signs and don’t hesitate to involve your vet. They can identify and treat any underlying illness causing your kitty’s fish funk.

With proper care both at home and from your vet, your cat’s mouth can smell fresh and healthy again! Just be diligent about monitoring their breath aroma and responding promptly if it seems significantly smelly or fishy. Together you and your vet can get to the bottom of kitty’s stinky breath.