Why Does My Dog Smell Like Fish?

Dogs just like humans can emit some pretty unpleasant body odors. And one of the worst offenders is when a dog smells like…well…fish. 

While we humans work hard to prevent and mask our body odors by bathing frequently and applying deodorants and perfumes, dogs don’t really seem to mind their own stench. After all, dogs are often attracted to things we find putrid such as trash and rotting animal carcasses.  

Naturally, dogs tend to have stinky odors around their feet, ears, and rears. That is because these areas contain specialized glands that produce oils and those areas are naturally colonized by yeast and bacteria. However, overgrowth of these yeasts or bacteria due to allergies or other disorders can make dogs particularly smelly and may signal an issue. 

What Causes Fishy Smell in Dogs?

Dogs can sometimes give off fishy aromas. If you are feeding your dog a fish-based diet or supplementing your dog’s diet with fish oil a fishy odor is likely not a cause for concern. 

Otherwise, if your dog smells like fish they may have an abnormal medical condition that needs to be addressed. Dental issues, gastrointestinal disorders, certain infections, and anal gland disorders can all lead to a fishy odor in dogs. Most often this is caused by an overgrowth of certain foul smelling bacteria. 

Reasons Your Dog Smells Like Fish

If you notice that your dog smells fishy, finding the source of the fishy smell is important and can help to narrow down the problem. Read below to discover the most common reasons why dogs smell like fish and what you should do about them.  

If Your Dog’s Breath Smells Like Fish 

Most of our dogs’ breath doesn’t smell great because—let’s be honest here—many of us pet parents do not brush our dog’s teeth on a regular basis. However, fishy smelling breath may signal a problem due to one of the following reasons: 

Dental Issues

Fish-scented breath may indicate a dental problem in your dog. Periodontal disease is caused by infection and inflammation of the structures that surround and support the teeth. Periodontal disease is the most common disease seen in dogs and is present in up to 84 percent of dogs over the age of three (1). If you lift your dog’s lips and see a large amount of tartar, which looks like yellow or brown material stuck to your dog’s teeth, or red or puffy gums, your dog may have periodontal disease. Periodontal disease should be treated by your veterinarian as soon as possible to stop it from progressing. This disease is best treated with regular professional dental cleanings under anesthesia and daily home dental care.

Broken or abscessed teeth may also lead to fishy-smelling breath in dogs, so make sure to have your dog’s mouth and teeth examined by a veterinarian to rule out any specific tooth problems. 

Gastrointestinal Disorders

Dogs with food allergies or food intolerances may burp excessively and have trouble digesting food which can lead to fishy breath. If your veterinarian suspects that your dog has a food allergy, she may recommend feeding your dog a prescription hypoallergenic diet.

Acid reflux, also called gastroesophageal reflux or GERD, may also cause foul smelling breath. Symptoms include regurgitation, drooling, lip licking and gulping air. Antacid medications given as directed by a veterinarian often help to control symptoms.

If Your Dog’s Butt Smells Like Fish 

If your dog’s butt is the culprit of the fishy smell, it’s likely an anal gland problem. Sitting just inside the anus, dogs have a pair of fluid filled structures called anal glands or anal sacs. These sacs contain fishy, foul-smelling liquid that ranges from thin and yellowish to thick and grayish in appearance. Dogs naturally express their anal glands when they poop and when they are frightened. 

In certain dogs, their anal glands may not express normally and this can lead to issues including impaction and rupture. While it is unknown exactly what causes some dogs to have anal gland issues, those with obesity, chronic diarrhea, constipation, environmental and food allergies all tend to be at an increased risk of anal gland disorders. 

Symptoms of an anal gland issue include scooting, leakage of anal gland contents, and excessive licking of the area. If your dog’s anal glands are impacted you may see a swelling next to her anus. A ruptured anal gland will cause an open wound next to the anus. If you see any of the above symptoms, you should take your dog to the vet.

Your veterinarian will perform a rectal exam and, if necessary, will express your dog’s anal glands. Dogs without signs of anal gland issues should not routinely have their anal glands expressed. Some veterinarians believe that over-expression, especially the external expression method that is performed by many groomers, may harm the anal glands and lead to issues in the future. 

Weight loss, high fiber diets, hypoallergenic diets and controlling environmental allergies with prescription medications and supplements may help to ease symptoms of anal gland irritation in dogs. In those dogs where none of the above treatments help with their anal gland issues, surgical removal of the anal glands may be recommended.   

If Your Dog’s Pee Smells Like Fish 

Dogs may develop fishy-smelling urine due to a urinary tract disorder. Urinary tract infections (UTIs), bladder or kidney stones, prostate disorders in males, and bladder cancers may all lead to foul-smelling urine. 

If you notice that your dog’s pee smells abnormally pungent, you should take them to their veterinarian. Your veterinarian will thoroughly examine your pet and usually begin with a urinalysis (urine test) and possibly a urine culture. If an infection is discovered, antibiotics will be prescribed to treat the infection. If this becomes a recurrent problem or is accompanied by other symptoms such as bloody urine or straining to urinate, your veterinarian may recommend X-rays and/or an ultrasound of your dog’s abdomen to help to diagnose the problem.  

When Is Fishy Odor In Dogs a Problem? 

If you notice a fishy odor coming from your dog and it lasts beyond a few days, you should take them to the vet. 

Veterinarians are trained to detect problems that pet parents may have a hard time picking up on and can guide you on the best treatment for your dog. Typically the sooner issues are diagnosed in dogs, the easier—and less expensive—they are to treat.

How To Help Your Dog Smell Good 

Luckily, there are things pet parents can do to help prevent their dogs from developing that unpleasant, fishy odor. 

You can alleviate bad breath by brushing your dog’s teeth frequently, ideally once daily, with a soft bristled or finger toothbrush and an enzymatic dog-safe toothpaste. Chlorhexidine-based oral rinses available from your veterinarian, dental chews, and prescription dental diets can also help to alleviate bad breath. 

If your dog already has gingivitis (inflamed gums) or more advanced periodontal disease, brushing alone will likely not resolve bad breath and a professional dental cleaning will be necessary. When your dog has their teeth cleaned make sure that your veterinarian takes X-rays of their teeth. This allows for the detection and treatment of tooth root abscesses and other issues that may not be apparent otherwise. 

If your veterinarian has ruled out a dental issue as the cause of fishy breath, they may recommend a special diet or medication to help with a suspected gastrointestinal disorder, which may help to improve your dog’s breath. 

It’s also important to keep up with regular grooming for long-haired dog breeds. However, ask your groomer not to express your dog’s anal glands regularly, since this may lead to more problems. If your dog is licking or scooting their butt, have their anal glands checked by a veterinarian. If they are full, your vet can express them, which should stop odor and discomfort. 

Additionally, it’s important to feed your dog a high-quality complete and balanced diet to keep their skin and coat healthy and their gut-health in check.