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Dogs Butt Smells Like Fish: Why Does It Happen?

Renee Whitmore
Last Updated on
by Renee Whitmore

We all love our doggos, but sometimes the smells they make can be pretty gross.

One smell, in particular, can be cause for concern: when your dog’s butt smells like fish. It’s not supposed to smell like that, right?

In this article, we’ll explain why your dog’s butt might smell like fish, if you should be worried, and what you can do about it. We’ll also go over symptoms you should look out for to prevent the smell from happening in the first place.

Keep reading if you’re tired of your living room smelling like a fish market every time your dog walks past.

Why Does My Dogs Butt Smell Like Fish?

Dogs Butt Smells Like Fish

There are a couple of reasons why your dog’s butt smells like fish. The most common cause is a buildup of anal sac fluids on the inside of your dog’s rectum.

Normally, these dogs use these fluids to communicate things to other dogs, like what sex they are and if they’re in heat. We’ve all seen our dog sniff another dog’s butt, and their anal glands are the reason why.

Sometimes these glands can become filled with too much fluid that can’t be expressed naturally through defecation. This can produce unpleasant odors that may even ward off other dogs. Your dog can experience some pain, and you may notice blood or puss in their stool.

The cause might be a digestive problem or a simple inability to pass the fluids naturally. In rare cases, it may be due to something more serious, like a tumor.

However, this is a very common issue, especially among small or overweight dogs. See your veterinarian, but don’t start freaking out when you catch a whiff of tuna when your dog walks by.

Should I Be Worried?

If it’s the first time you’ve noticed that your dog’s butt smells like fish, you should call your veterinarian. It could be that they just need to express your dog’s anal sacs, and the smell should go away.

Small dogs need to have their anal sacs regularly expressed, either by a veterinarian or a dog groomer. You can learn to express the anal sacs on your own, but you should give your vet a visit first to make sure it isn’t something more serious.

Impacted anal sacs should only be expressed by a veterinarian because the process can require a saline rinse or softening agent, along with a careful touch.

Heavily compacted anal sacs may become infected or abscess, at which point you need to get medication from your vet. After the infection has cleared and they’re able to express the sacs safely, you’ll likely put your dog on a high fiber diet to help clear the fluids naturally.

It could be that your dog has tumors growing on its anal sac. While this sounds alarming, it’s more common than you think. Sometimes, veterinarians have to remove the anal sacs entirely to prevent further infections from occurring.

What Are Some Symptoms to Be Aware Of?

There are several symptoms to watch out for, some of which will be obvious but others not so much.

The first symptom to check for is, of course, your dog’s butt smelling like fish. We’re not saying to get up close to see for yourself, but just be mindful of any changes in your dog’s odor.

If your dog’s daily ritual includes dragging their butt across your beautiful carpet or grass, it could be a problem with their anal sacs. It causes your dog a bit of discomfort, leading them to scoot across a rough surface in an effort to expel the fluids.

Difficulty or visible pain while pooping is another tell-tale sign of an anal sac problem. If you spot any blood or pus in the stool, you should take your pup in for a checkup.

Small or overweight dogs are especially prone to impacted anal sacs, and they can develop a smelly butt more often than other breeds. If your little furball smells a bit like fish, then the odds are that its anal glands need to be expressed.

What Should I Do if My Dog’s Butt Smells Like Fish?

Vet visit

The first thing you should do if your dog’s butt smells like fish is visit the veterinarian. If this issue isn’t serious, then you can have them express your dog’s anal glands and go about your day. Scheduling a regular visit with your vet is essential for a happy dog butt.

Alternatively, you can learn to express anal sacs yourself if you can stomach the smell. It’s a relatively simple process that you can have your vet walk you through on your next visit.

However, keep in mind that expressing these fluids too much is bad for your pup. It can dry out their rectum, causing intense discomfort and scratching. Look for the signs that they need to be expressed before releasing them again.

How to Prevent Anal Sac Disease

While it isn’t always possible to prevent anal sac disease or a fishy dog butt, there are some things you can practice to decrease the likelihood that it’ll happen:

  • Feed your dog a healthy diet with good fiber levels
  • Take note of any changes to your dog’s stool
  • Walk and exercise your dog frequently and watch for any weight gain
  • Make sure your dog has access to plenty of fresh water

If you’re bringing a new dog into the family, research if their breed is more prone to anal sac disease than others. Smaller dog breeds commonly have these sorts of problems, while larger dogs don’t.


Thankfully, it isn’t the end of the world when your dog’s butt smells like fish. Seeing a vet is the best way to solve the issue as quickly as possible and it’s usually not that serious of a problem.

In fact, that fishy smell is a great reminder to schedule your next vet appointment, ensuring your dog stays happy and healthy for years to come!

About Renee Whitmore
Renee Whitmore
Renee Whitmore is an American college professor and freelance writer from North Carolina. She holds a Bachelor’s Degree in English and a Master’s Degree in English Education. When she is not driving her teenage son to wrestling practice or learning the ins and outs of Fortnite from her younger son, she is working on her first book to be published soon.
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