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Have you ever noticed that your dog has bad breath? Some pet owners have noticed and complain that their dog’s breath smells like fish. A fish odor can occur for several reasons, which we will review in detail below.
The medical term for bad breath is “halitosis.” Bad breath can be caused by a dog’s diet, ingestion of different foods or trash, mouth or dental disease, disease of the upper respiratory tract, infections, or other metabolic problems, such as diabetes.
What Causes Fishy-Smelling Breath in Dogs?
There are dozens of causes of canine bad breath, since it is merely a symptom of a larger issue. For example, breath that smells like fish may be caused by something your dog ate, an ulcer in the mouth, or from a tooth infection. Some of the possible causes of fishy smelling breath are minor and others are more serious and require treatment.
Causes of Bad Breath in Dogs include:
- Dietary indiscretion. A common cause for bad breath in dogs is eating something malodorous, such as a dead animal, garbage, animal feces, compost, litter-box waste, or spoiled food. These can all cause breath that smells like fish.
- Gum disease. Gingivitis is an inflammation of the gum tissue, which is commonly caused by dental plaque. This results in swelling and redness of the gums as well as bad breath. Plaque develops when the normal bacteria in the mouth mix with proteins and starches found in saliva. This mix produces plaque material that adheres to the teeth. Eventually, plaque turns into tartar, which firmly adheres to the teeth. It is most obvious just below the gum line where it accumulates.
- Tooth root abscess. An abscessed tooth can cause bad breath.. Some tooth root abscesses are contained within the mouth and others will abscess up through the skin. It is common for a dog to present to the veterinarian for a swelling and a draining wound on the cheek just below the eye. Inspection of the wound or a sedated oral examination can reveal an abscessed tooth. Treatment includes tooth extraction (removal) or a root canal. Once the tooth is treated, your veterinarian will likely prescribe antibiotics and pain medication depending on the severity of the infection.
- Oral ulceration. Ulcers in the mouth can result from infection, reactions to certain drugs, or from ingesting or licking caustic substances. Caustic substances can include cleaning chemicals, soap and detergents, or liquid potpourri.
- Many cleaning chemicals such as bleach or lye can cause oral ulcerations.
- Laundry and dishwasher pods are colorful, soft and can look like a dog toy. Dogs can chew on or ingest these laundry or dishwasher detergent pods, which can cause severe oral ulcerations. To learn more – go to Laundry or dishwasher detergent pod toxicity in dogs.
- Liquid potpourri is a common household item. Potpourri is scented and can be appealing to some dogs. Potpourri ingredients can include essential oils and cationic detergents that cause severe ulcerations of the mouth, gum tissues, and/or esophagus.
- Oral infections. Oral tissue can be traumatized and infected by burns or from trauma resulting from chewing on bones, sticks, or other sharp objects. Another cause of oral tissue trauma is from bite wounds from fights with other animals.
- Foreign material. Bone, sticks, or hair can become caught in the mouth causing a foul odor. This is a common reason for fishy-smelling breath.
- Oral tumors. Tumors in the mouth can become infected or parts of the tumor can begin to die (necrose), which can lead to a foul odor.
- Digestive problems. Some dogs with stomach or digestive problems including gastroesophageal reflux, stomach ulcers, and hemorrhagic gastroenteritis can have bad breath. Vomiting can also result in foul smelling breath.
Other Causes of Bad Breath in Dogs
- Lung cancer. Cancer of the throat, mouth, lungs, and nose can cause foul breath.
- Respiratory infections. Various infections of the respiratory tract can cause foul smelling breath. It can be especially noticeable during exhalation or coughing.
- Kidney disease. A decline in kidney function can cause some dog’s breath to have the odor of ammonia.
- Diabetes. Another disease that can cause an abnormal oral odor is diabetes. A severe form of uncontrolled diabetes, diabetic ketoacidosis, can cause an abnormal sweet, fruity odor.
- Liver disease. Liver dysfunction can result in a sweet, musty breath, which is caused by dimethyl sulfide accumulation.
How to Make Fishy Breath Go Away
The best way to make bad breath go away is to identify and treat the underlying problem that is causing the bad breath. Often, you can identify the cause of your dog’s bad breath by noting the following:
- Has your dog eaten anything abnormal, such as compost? A dead animal carcass? Gotten into the litter box? Trash?
- Does your dog have signs of dental disease? Look in your dog’s mouth, if you can do so safely. If you carefully lift up your dog’s lip, you can sometimes see red inflamed gums and tartar build-up on the teeth. Many times, the worst teeth and odor problems occur in the back of the mouth. If possible, look at the top teeth in the very back of the mouth for signs of redness, inflammation, and tartar build-up. In addition to bad breath, tartar build-up, redness, and/or swollen gums are all signs of problems.
- Is your dog showing any signs of respiratory symptoms, such as coughing or trouble breathing? Sneezing? Bloody nose?
- Is your dog showing any signs of diabetes, such as drinking more or urinating more?
- Is your dog vomiting? Not eating? Losing weight?
If you notice any abnormalities in your dog, please see your veterinarian. An abscessed tooth can be very painful. If you don’t notice any problems, but are still worried about your dog’s bad breath, make an appointment and allow your veterinarian to examine your dog and evaluate for possible underlying problems.