5 Reasons Why Your Dog Smells Like Fish (Vet’s Advice)

Why does my dog smell like fish?

Dogs are not known for being sweet-smelling at the best of times but if you’ve recently noticed a slightly more pungent and fishy odor, you might be wondering what the cause is. The truth is there could be several reasons why your dog smells a bit unusual. Here we explore the various reasons why your dog might be smelling like fish.

1. Anal gland issues/Anal sac disease

There are two glands just inside the anus that contain material for scent marking. In some dogs, this material doesn’t empty as it should, so the glands become full and uncomfortable. This liquid substance has a strong odor and so full anal glands are one of the most common reasons for a fishy odor.


As well as the smell, other signs may include your dog scooting or rubbing their bottom on the ground, licking excessively at their anus, and general discomfort in their back end.

Which dogs are most vulnerable?

This condition can affect any dog, but small breed dogs seem more prone to anal gland issues than larger ones. Some dogs that suffer from poor stool quality (loose poo) can be more prone to anal gland problems.

How to treat the issue

vet-treating-the bottom-of-the-dog

The anal glands will need to be expressed (emptied) to relieve the build-up of secretions. This is best done by a veterinarian who can also assess your dog for complicating issues such as infection in the glands. Usually, your dog will feel much more comfortable immediately but may require medications if there is an infection issue.

How to prevent the issue

Some dogs need their glands intermittently expressed to keep them comfortable. Increasing the amount of fiber in the diet can help to create a bigger, bulkier stool that will press on the glands as it passes through to express them naturally. Speak to your veterinarian about fiber supplements.

2. Dental issues

Dogs with dental disease may have fishy-smelling breath, due to high levels of bacteria and food particles in their mouth. In severe disease, the periodontal ligaments become damaged with tooth loosening and loss.


As well as a malodorous mouth, you may notice other signs that could indicate dental disease. This includes a build-up of tartar on the teeth, inflamed gums, difficulty chewing (or chewing on one side), sudden facial swelling (tooth root abscess), and weight loss.

Which dogs are most vulnerable?

Older dogs are more likely to suffer from dental disease. Certain breeds are more prone to bad teeth too, including sighthounds like greyhounds and whippets, and small dogs like pugs, chihuahuas, and terriers.

How to treat the issue

vet-checking-the-mouth-of-dog (1)

Dogs with dental disease will need an assessment from a veterinarian. They could require dental surgery under anesthetic to scale and polish (clean) the teeth, and extract any rotten ones. Removing bad teeth and cleaning the mouth in this way will reduce the bacteria present and create fresher breath.

How to prevent the issue

You should introduce your dog to teeth brushing from an early age. Daily teeth brushing will help to reduce bacteria and stop tartar formation.

3. Gastrointestinal issues

Gastrointestinal issues could cause your dog to have a new odor, particularly if he is more gassy than normal. There are a variety of different conditions that could cause digestive upset, including food intolerances, parasite or bacterial infections, and inflammatory bowel disease.


Dogs with digestive upset may have loose stools and intermittent vomiting. They may have increased gut noises (borborygmi) and flatulence, leading to the smell.

Which dogs are most vulnerable?

Any dog could be affected by gastrointestinal disease.

How to treat the issue


In mild cases of stomach upset or excessive wind, a change of diet could help improve things. But if things aren’t resolving or your dog seems poorly then you should get him seen by a veterinarian. Your dog may require tests to diagnose his problem. Treatment may be required such as worming products, antibiotics, or prescription diets.

How to prevent the issue

Having your dog on a good-quality diet that is appropriate for his age and size is a good starting point. Ensure your dog has regular preventative worming treatment to prevent unwanted parasites. Probiotics can be useful for some dogs too.

4. Urinary issues

Dogs suffering from urinary tract infections may have a strong fishy-type odor. Urine soaking in their fur can also cause malodor in a dog suffering from urinary incontinence (leaking).


Dogs with urinary problems may have incontinence (leaking of urine on their bed or in puddles on the floor), cystitis issues (straining and going little and often), blood in the urine, or changes in thirst.

Which dogs are most vulnerable?

Elderly dogs are more prone to incontinence issues than younger ones. Cystitis can be seen at any age but is more common in female dogs than male dogs.

How to treat the issue

You will need to seek help from your veterinary surgeon. They will usually run some tests looking at blood and urine samples to try and work out the underlying cause of your dog’s urinary complaint. If an infection is diagnosed then antibiotics will be required. Other treatments such as anti-inflammatories or medication to help with incontinence may also be required.

How to prevent the issue

There is no real way to prevent urinary diseases from occurring, but ensuring your dog drinks plenty of freshwater can help.

5. Female bacterial/uterus issues


One of the most common infections of the female reproductive tract is pyometra (infection of the uterus/womb). This can be an “open pyometra” whereby pus and fluid leak from the dog’s genitals, which may cause an odor. A “closed pyometra” can be trickier to notice as the pus remains in the uterus, building up to dangerous levels.


As well as the change in odor, an unusual discharge may be noted coming from your dog’s genitals, or your dog may be licking excessively down below. She may also be off-color and have a high temperature, as well as being off her food.

Which dogs are most vulnerable?

Entire female dogs of any breed, but especially older ones.

How to treat the issue


Your dog will require urgent treatment from a veterinarian if they are suffering from a pyometra. Surgery is usually recommended to remove the diseased uterus, but sometimes medical treatment may be considered too.

How to prevent the issue

You should spay your dog at an early age. Removal of the ovaries and uterus will prevent pyometra from occurring.

When is dog odor a medical condition?

If your dog suddenly develops a noticeable fishy odor it could be a sign of underlying disease, particularly if it is accompanied by any of the clinical signs discussed in previous sections. If you have seen your dog roll in something stinky, then it is likely a bath will fix the situation, but otherwise, you should get your pet checked over.

When to take your dog to the veterinarian

You should get your dog examined by a veterinarian if you notice any of the symptoms mentioned in the previous sections. Earlier treatment leads to a better outcome in all cases, so it’s best to get your dog checked out if you notice a new smell about them.


There are many reasons why your dog may have developed a new fishy odor. Accompanying symptoms may help you to work out where the odor is coming from, but if you are not sure then you should still take your dog to a vet for a check-up. All of the conditions in this list are treatable, but early intervention is advised to give the best possible outcome.

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