Why Does My Dog Smell Like Fish?
Does your dog smell like fish? While you may think it’s likely caused by what your little friend ate or rolled in, the “fishy” smell on your dog is probably a sign of an underlying health issue. The health issue could be a yeast infection in his ears, feet, or skin, and in serious cases, a sign of anal sac disease.
Since anal sac disease is the most common reason your dog smells like fish, let’s take a few minutes to better understand what this condition is, the causes, and the recommended tips to prevent it.

What are Anal Sacs?
Anal sacs, also called anal glands, are small glands located on each side of your dog’s anus. The glands release a smelly secretion every time your dog poops, with the secretion acting as a scent marker for your dog. The smell helps dogs know important chemical information about each other and explains the uncanny interest your dog shows in another dog’s poop.
What is Anal Sac Disease?
Anal sac disease is a blanket term that describes any anal gland problem, including impactions, anal sac tumors, and infections & abscesses. The disease is more common in small dog breeds and overweight dogs and is an indication that your dog is having trouble expressing his anal glands when he poops.
1. Impactions
Your dog will suffer from impaction when the fluids in the anal sac are not completely emptied when he defecates. The fluid can become dry and cause impaction. Impacted anal sacs feel hard to touch and cannot express properly, which can be very painful for your dog.
Your dog’s anal sacs can become impacted for several reasons. It could be a result of an abnormality in your dog’s anal sacs or your fluffy friend has a soft stool, which isn’t firm enough to express the anal glands when he defecates.
Obese dogs are at a higher risk of suffering from impacted anal glands because their anal sacs do not empty well. Impacted anal glands that go untreated can become abscessed.
2. Infections and Abscesses
Anal glands can get infected, and if the infections are left untreated then the glands become abscessed. The area where the infected and abscessed anal glands are located may appear swollen or discolored, and your dog will be in so much pain. Untreated infections and abscesses can rupture through the skin, causing further health complications.
If your dog gets anal sac infections and abscesses, it will need antibiotics and pain medications, and in some cases require surgery to cure the condition. That’s why it’s recommended to take your dog to see a vet the moment you notice signs of anal sac disease.
3. Anal Sac Tumors
Anal sac tumors can also make your dog smell like fish. Although uncommon, the tumors make it hard for dogs to express their anal glands naturally. They make the anal glands feel enlarged and firm, and in serious cases, anal sacs with tumors will not express at all. The tumors can be cancerous and metastasize to other parts of the body.
Your veterinarian may have to take a biopsy and perform an ultrasound to diagnose the issue. The most common treatment is surgery to remove the tumor, though serious cases can result in the removal of the anal glands.
Signs of Anal Sac Disease in Dogs
If you notice your dog smells like fish, it could be an early indicator of an anal sac disease. However, sometimes you might not notice the smell. So, what are the other signs of anal sac disease in dogs you should be on the lookout for?
- Scooting their butt on the floor or ground
- Signs of blood or puss in their stool
- Vocalizing while defecating
- Difficulty defecating
- A hard lump near the rectum
- Biting or licking beneath the tail
Dogs Vulnerable to Anal Sac Disease
Not all dogs are prone to anal sac disease in equal measure. Certain breeds and dogs with specific health conditions are more prone to the condition than others. They include:
- Small dog breeds such as chihuahuas, spaniels, terriers, etc.
- Dogs with environmental and/or food allergies
- Dogs that are obese or overweight
- Dogs with yeast or bacterial infections
- Dogs suffering from hypothyroidism
How to Prevent Anal Sac Disease in Dogs
Although you cannot protect your dog from anal sac disease completely, there are a few things you can do to reduce the risks of them getting the disease. They include:
- Exercise your dog regularly to prevent obesity
- Feed your dog a balanced diet with enough fiber
- Have your dog drink plenty of clean, fresh water
- Examine your dog’s stool to catch any signs of blood, puss, or softness
So, why does your dog smell like fish?
Your dog smelling like fish could be a sign of a yeast infection in his ears, feet, or skin, or a sign of anal sac disease, which includes impactions, anal sac tumors, and infections & abscesses. Anal sac disease is more common in small dog breeds and overweight dogs.