You’ve caught it — that unmistakable fishy whiff following your dog around, and now you’re on your phone trying to work out if it’s normal or if something’s wrong. First: take a breath. Most of the time this is a common, manageable thing, and your dog is fine.

But “fishy” can point to a few different causes, and one or two are worth acting on quickly. So rather than guess, let’s work out which one you’re actually dealing with — and what to do about it.

The Most Likely Cause

Your dog has two small glands, each about the size of a pea, just inside their bottom. They’re full of a pungent, oily fluid that normally releases a little at a time when your dog poos — it’s how dogs leave their calling card at every lamppost. Usually you’d never notice.

The trouble starts when those glands don’t empty properly. The fluid builds up, thickens, and the smell gets stronger — that sharp, fishy, slightly metallic note that’s now on your dog, your hands, and quite possibly your sofa. It’s most common in smaller breeds, dogs with soft stools, and dogs carrying a bit of extra weight.

The giveaway that it’s glands rather than anything else: the smell is coming from the back end, and it often comes with scooting along the floor or a lot of sudden licking back there.

When Fishy Doesn’t Mean Glands

Before you settle on anal glands, it’s worth ruling a few things in or out. This is the bit most people skip, and it’s the bit that actually matters.

It might just be their food. Diets heavy in fish, or fish-oil and omega-3 supplements, can genuinely make a dog smell faintly of fish. If the smell is mild, all over rather than from the rear, and your dog is otherwise completely themselves, their dinner is the likely culprit — and there’s nothing to fix.

A fishy smell from the mouth is a different problem. Fishy breath usually points to dental disease, and occasionally to something else going on internally. If it’s coming from the front end, not the back, that’s one to mention to your vet rather than treat as glands.

If it’s a female dog, don’t assume glands. A fishy smell from an unspayed female — especially from the vulva or her wee — can be a urinary infection, vaginitis, or, most importantly, pyometra: an infection of the womb that’s a genuine emergency. If your unspayed female smells fishy and is off her food, drinking or weeing more than usual, unusually tired, or has any discharge, don’t wait — call your vet the same day. This one’s rare, but it’s the reason “just anal glands” isn’t a safe assumption for every dog.

When to See a Vet

A quick puff of fishiness after a fright or a stressful vet trip is normal and fades fast. Book a vet check if:

  • the smell hangs around for days rather than clearing
  • there’s lots of scooting, licking, or biting at the rear
  • you spot swelling, redness, or any blood back there
  • it came on suddenly alongside other changes — off food, low energy, drinking more
  • any of the female-specific signs above

None of that is meant to alarm you. It’s just the honest line between “manageable at home” and “let someone qualified take a look.”

What Actually Helps

If it is the glands — the usual case — a few things genuinely help.

Firmer stools do a lot of the work. Glands rely on the pressure of a normal, firm poo to empty naturally, so a diet with enough fibre, and keeping your dog at a healthy weight, is one of the most effective things you can do. It’s worth a proper chat with your vet about diet rather than guessing.

Don’t be tempted to squeeze them yourself. It’s the obvious “fix”, but done wrong it can cause real damage, and vets are clear: don’t attempt it unless a vet has shown you how on your own dog. If the glands keep filling, this is a job for your vet or a veterinary nurse — here’s what expressing actually involves, and recurring problems are worth looking into properly. Worth knowing: most groomers no longer do this and will refer you to a vet.

Keep an eye on the pattern. For most dogs this becomes a bit of routine upkeep — like nail clipping — rather than a crisis. Knowing your dog’s normal makes the not-normal easy to spot.

Why the Smell Keeps Coming Back

Here’s the part nobody warns you about. You deal with the dog, you clean the sofa, and a few days later the smell is somehow back. You’re not imagining it.

That gland fluid isn’t just smelly — it’s built to stick. It carries proteins that grip onto fabric and hold the odour compounds in the fibres, then re-release the smell whenever it gets warm or damp again. (The reason it reads as specifically fishy, by the way, is a compound called trimethylamine — the very same one that makes off fish smell of fish. Your nose isn’t wrong.) Ordinary air fresheners and fabric sprays mostly lay a nicer smell on top, so the fishy note is still sitting underneath, waiting to come back.

Getting rid of it properly means neutralising those compounds rather than masking them — which, it turns out, most general cleaners simply aren’t built to do. That surface-smell problem is exactly the bit we’re building Fishy Fix™ Surface Cleaner for.

Frequently Asked Questions

Why does my dog smell fishy all of a sudden?
A sudden fishy smell is most often anal glands releasing — sometimes triggered by stress, a fright, or a soft stool. If it clears within a day and your dog is otherwise fine, it’s usually nothing. If it lingers, or comes with scooting, swelling, or the female-specific signs above, see your vet.
How do I stop my dog’s glands from smelling?
The most reliable route is firmer stools, so the glands empty naturally — which usually means the right amount of fibre in the diet and keeping your dog at a healthy weight. Your vet can advise on diet, and can express the glands or investigate if the problem keeps returning.
What can I give my dog to stop the fishy smell?
There’s no magic supplement, but a vet-guided diet with adequate fibre is the thing that helps most dogs, because it tackles the cause rather than the smell. Be wary of quick-fix chews promising to “fix glands” — talk to your vet first.
How do I know if my dog needs their glands expressed?
Frequent scooting, licking or biting at the rear, a persistent fishy smell, or visible discomfort are the usual signs. Get your vet or a veterinary nurse to check — don’t attempt expressing them yourself unless a vet has shown you how. Most groomers no longer offer this and will refer you to a vet.
Why does my female dog smell fishy?
It can be anal glands, as with any dog — but a fishy smell from the rear or urine in an unspayed female can also mean a urinary infection, vaginitis, or pyometra (a serious womb infection). If she’s unspayed and unwell in any other way, treat it as urgent and call your vet.
How do I get the fishy smell out of my sofa or carpet?
Because the compounds soak into fabric and re-release when damp, ordinary sprays tend to mask rather than remove it. You need something that neutralises the odour compounds rather than covering them — which is exactly the gap we’re building Fishy Fix™ Surface Cleaner to fill.

Sources & Further Reading

We like to show our working. This page draws on UK veterinary advice and published research:

This is general information, not a substitute for veterinary advice — if you’re worried about your dog, speak to your vet.