German Spitz smelly dog with owner

If a dog smells fishy for a while, it's worth seeing a vet.

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Why does my dog smell of fish?

By Dr. Katy Ellison MA VetMB MRCVS Veterinarian

Updated on the

A fishy smell on a dog is never normal, but there's not just one reason why your pet may have this odour.

Dogs are often described as “man’s best friend”, but this relationship is sorely tested if your dog’s perfume is more akin to old fish than fresh spring grass.

There is no cause for alarm though because unpleasant odours in an otherwise well dog are usually simple to solve.

How do I get rid of the smell of fish on my dog?

Dogs have some pretty unsavoury habits, but a healthy dog should not have a strong odour and certainly should not smell of fish. Once you have eliminated your dog rolling in something revolting as the root cause of the smell, you need to try to ascertain what part of your dog’s anatomy it originates from.

There are a few prime candidates and top of the list, especially if your dog is one of the smaller breeds, would be your dog’s anal glands. These are scent glands located either side of your dog’s anus that should empty every time your dog passes faeces. The secretions from these glands have a distinctive fishy odour and if the glands become blocked or infected, the contents can leak out, releasing the pungent aroma. Other signs of anal gland disease include your dog licking or biting round their bottom a lot, and they may start to rub their rear end along the floor in an attempt to relieve the irritation.

Although anal gland disease is by far the likeliest cause of your dog’s unpleasant perfume, there are other possibilities. Bacterial infections anywhere can result in a strong aroma. As such, skin, ears, mouth and paws are worth checking thoroughly if your dog’s odour has changed.

The important point is that a fishy aroma is not normal and a visit to a veterinary clinic to have your dog checked over is warranted.

Why do female dogs give off a fishy smell?

A healthy female dog should not give off a fishy smell and, if you notice a strong odour, this will almost always be a sign of a health problem. Just as with male dogs, the anal glands of female dogs contain a fishy smelling liquid that under certain circumstances can leak out. Anal gland disease is the first thing to rule out.

Urinary tract infections (UTIs) can cause the urine to smell very strongly. If the smell is accompanied by other signs of a UTI (such as blood in the urine or straining to urinate), you should try to collect a urine sample from your dog for the veterinary surgeon to analyse. Getting your dog to wee into a pot may, of course, be easier said than done.

If your dog has not been spayed, a veterinary surgeon will want to rule out an infection in her uterus (pyometra). Typically dogs with pyometra will be under the weather, off their food and they will have an increased thirst. In addition, many of them will have a purulent (pus-filled) discharge from their vagina, which may have a fishy odour.  

Why does my dog smell like fish when scared?

The most likely source of a fishy odour when your dog is scared will be their anal glands. These are scent glands that your dog should empty every time they pass a motion. Fortunately you will not normally notice any smell from your dog’s glands, but sometimes when a dog is scared they will empty their glands spontaneously and you may notice the characteristic fishy smell. This emptying of anal glands in a fearful situation is normal and does not require veterinary intervention.

Why does my dog's breath smell like fish suddenly?

Believe it or not your dog’s breath should not have a significant odour. The most common cause of bad breath in your dog will be poor dental hygiene and gum disease, just as is the case in humans. This would normally develop gradually over the course of weeks or months. If your dog’s breath develops a fishy smell very suddenly it may well be caused by an infection in the mouth or a dental abscess. You might notice other changes, such as difficulty eating or dropping food as your dog eats, because an abscess is very painful. But dogs are very tolerant of dental pain and frequently show few signs that are visible to us, so just because your dog appears fine do not assume that they are. As with any sudden changes in your dog’s health, you should seek veterinary advice promptly.

Why does my English Bulldog smells like fish?

The commonest reason for a dog to smell like fish, whatever their breed, is a problem with their anal glands. If these become blocked or impacted, instead of emptying them when they defaecate, the contents can leak out and you may notice a strong fishy odour.  

English bulldogs are one of the breeds in which we see a higher than average incidence of allergic skin disease. This predisposes English bulldogs to anal gland disease. In addition, they have skin folds, which make the perfect breeding ground for bacteria and yeast, and such infections can cause a fish-like odour.

Why does my dog smell like poop?

Dogs may not always be the most hygienic of creatures, but they definitely should not smell of poop. It may sound obvious but, especially if your dog is long-haired, check under their tail to make sure they have not got any matted fur in which some faeces have got trapped. This may be more likely to happen if your dog has diarrhoea, so a smell of poop could be a sign that your dog has an upset tummy.

Why does my dog still smell after their glands were expressed?

If your dog has had his anal glands emptied by a veterinary surgeon but the unpleasant odour has not gone, you should arrange a follow-up appointment. The commonest reason for persistent anal gland odour will be an infection within the glands. This may require a course of antibiotics to clear it up. Or sometimes your dog’s anal glands may need to be flushed out and packed with antibiotic ointment. This procedure will normally be done under sedation.

Why does my dog smell like fish after being outside?

If your dog smells like fish for a short time after being outside, it is likely that some of the liquid contents of their anal glands has leaked onto their fur. If it is shortly after passing a motion, this is the most likely explanation. If the smell persists for any length of time though, it is sensible to get your dog checked by a veterinary surgeon.

What does a dog in heat smell like?

When a female dog is in season or heat, she should not smell any different to normal. Most female dogs will have a bloody discharge for a few days when they are on heat, but if this discharge has a significant odour it could suggest that there is an infection present. Pyometra (literally translated as pus in the uterus) is relatively common in bitches that have not been spayed. The discharge from a bitch with pyometra may be purulent (contain pus) and this can have an odour. If your bitch smells different to normal when she is on heat or in the weeks following her heat, especially if she appears under the weather, you should seek prompt veterinary advice. The majority of bitches with pyometra are successfully treated with surgery to remove the infected uterus, but the prognosis is much better if surgery is performed sooner rather than later.

How do I get rid of the smell of fish on my dog?

A fishy smell is never normal, so the key to getting rid of it is to find the cause. It may be stating the obvious, but make sure your dog has not rolled in anything unsavoury. If it is not something that a good bath can sort, you should seek veterinary help. Blocked anal glands are by far the most common cause for a fishy odour and having them emptied may be all that is required.

If there is no evidence that the anal glands are the issue, a thorough examination will hopefully shed some light on the source of the smell. A veterinary surgeon will have a particularly close look in your dog’s ears, will check their skin and paws, and probably take a look inside your dog’s mouth. They will be looking for any sign of infection.  

Why does my dog's bottom smell like fish?

Dogs have two small scent glands located either side of their anus. They are approximately pea-sized when full and contain a strong smelling liquid with a characteristic fishy odour. Every time your dog does a poo, the glands should release their pungent contents, but you will probably not notice the smell because there should be no residue left on your dog. If the glands become blocked or impacted, they cannot empty fully. This is often uncomfortable and small amounts of liquid may leak from the gland, resulting in an unpleasant smell coming from your dog’s rear end. This is easily solved by a visit to a veterinary surgeon, who will be able to empty or express the anal glands for your dog.

Why do you have to clean a dog's glands?

Most dogs’ anal glands function exactly as nature intended. In other words every time your dog passes faeces, the glands empty automatically, releasing their strong smelling liquid contents to mark the dog’s territory. Sometimes the glands become blocked and this natural process does not occur, resulting in the glands becoming very full or impacted. This can be intensely irritating to your dog and you may notice them scooting (rubbing their bottom along the floor) or licking and biting round their bottom. It is important to consult a veterinary professional at this point, so that they can empty the glands and relieve the blockage. If untreated at this point, the impaction can progress to more painful conditions such as an anal gland abscess. In some dogs that need their anal glands emptying frequently, it is possible to teach dog owners to empty the glands themselves, but you should always consult a veterinary surgeon for advice regarding this.

Some dogs will go through their whole life and never have to have their anal glands emptied, while others will get more frequent problems. So how can you help prevent your dog from getting blocked glands? Anal gland disease is more common in overweight dogs, so keep your dog nice and slim. Dogs with skin allergies will frequently suffer with anal gland problems too and effective management of any skin disease will help to control this. In dogs with no previous history of problems, anal glands can become blocked following a bout of diarrhoea, because a loose motion may not cause the glands to empty properly. If your dog is unlucky enough to be troubled by their glands regularly, adding fibre to their diet to bulk out their stools may help.

When should I see a vet?

A fishy smell is not normal, so in all cases it is advisable to see a veterinary surgeon. The majority of cases will be caused by a problem with your dog’s anal glands, and your dog will often show signs of anal gland irritation or discomfort. These signs include scooting (rubbing their bottom along the floor), licking or biting round the base of their tail or bottom, and suddenly turning and looking at their tail area. It is important to see a vet promptly because untreated, a blocked anal gland can develop into an abscess. The good news is that anal gland disease is usually relatively simple to treat.

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