Why Does My Dog Smell Like Fish? Causes of Dog Odor

What it usually means

Every dog has two anal sacs, at roughly the four and eight o'clock positions around the anus. They fill with a strong, fishy-smelling liquid that normally empties a little each time the dog passes stool, which is part of how dogs identify each other. A frightened or startled dog can also empty them suddenly, leaving a pungent smell on the furniture or your lap.

If the sacs do not empty properly, the fluid thickens and the sacs become full, itchy, and sore. That is when owners notice a lingering fishy odor, along with scooting, licking under the tail, or turning to look at the rear end. Small breeds, overweight dogs, and dogs with soft stools or skin allergies have these problems most often.

Other reasons a dog smells

Not every bad smell is the anal glands. Bad breath usually means dental disease. A yeasty or musty smell from the ears often means an ear infection. A greasy, rancid, or cheesy smell from the skin can mean a bacterial or yeast skin infection, often linked to allergies, and paws can smell like corn chips when yeast builds up between the toes.

Breeds with deep skin folds, such as Bulldogs, Pugs, and Shar-Peis, can develop smelly infections inside the folds. A strong urine smell can mean a urinary tract infection or leaking urine. And, of course, a dog who has rolled in something dead or in fox or goose droppings will smell until bathed.

When to call your vet today

Book a vet visit if the fishy smell lasts more than a day or two, keeps coming back, or comes with scooting, licking or biting under the tail, or pain when sitting or passing stool. Full anal sacs are easy for a vet to empty, and doing it before they become infected saves your dog a lot of discomfort.

Also call if a bad smell comes from the ears, skin, mouth, or skin folds, or if your dog smells unusual and is also itching, drinking more, or off their food. A smell is often the first sign owners notice of an infection that needs treatment.

When it's an emergency

Seek care the same day if you see a red, hot, swollen lump beside the anus, an open wound or bloody discharge there, or if your dog cries out, will not sit, or strains to pass stool. These are signs of an anal sac abscess, which is very painful and can burst through the skin.

Also go promptly if your dog has a fever, is lethargic, or stops eating alongside a bad smell, as that can mean the infection is spreading. A dog who is very sore may snap when the area is touched, so do not try to examine or squeeze it yourself.

What you can safely do at home

Bathe your dog with a gentle dog shampoo if they have rolled in something, and keep the fur around the rear end trimmed and clean, especially in long-haired breeds. Wipe the area gently with a damp cloth if there is a small amount of discharge.

Do not try to express the anal glands yourself unless your vet has shown you how and agrees it is right for your dog: done wrongly, it can bruise or damage the sacs. Avoid perfumes, sprays, and human deodorizing products on your dog, which only mask the smell and can irritate the skin.

What the vet will likely check

Your vet will examine the anal sacs, usually with a gloved finger, and empty them if they are full. If they are infected or abscessed, the vet may flush them, prescribe antibiotics and pain relief, and suggest warm compresses at home and a cone to stop licking. An abscess may need to be lanced.

For other smells, your vet will check the mouth, ears, skin, skin folds, and urine, depending on where the odor is coming from. Swabs and samples looked at under a microscope often show whether bacteria or yeast are involved, and the treatment follows from that.

Preventing a fishy smell

Firm, well-formed stools help the anal sacs empty naturally, so feed a complete diet and talk to your vet about adding fiber if your dog's stools are often soft. Keeping your dog at a healthy weight also helps, because extra weight around the rear makes emptying harder.

If your dog has allergies, managing them reduces both skin and anal sac problems. Some dogs need their glands emptied regularly by a vet or groomer, and dogs with repeated abscesses may be offered surgery to remove the sacs.

This page is general information, not veterinary advice, and it cannot replace an examination by the vet who knows your pet.