Why Does My Dog’s Breath Smell Like Fish? Causes + What To Do

If your dog’s breath suddenly smells fishy, it’s not just “normal dog breath.” It usually points to a specific cause and the fastest way to fix it is figuring out which one fits your dog.

Here are the most common reasons Aussie dog parents run into fishy breath, plus what you can do today.

5 common causes of fishy breath (and the clues to look for)

1) Anal glands (the sneaky one)

Dogs have small anal glands that produce a strong-smelling fluid. If they’re irritated, impacted, or your dog is licking that area more than usual, that smell can end up on their breath.

Clues this might be it:

• Scooting
• Licking their bum more than normal
• Fishy smell that seems to come and go
• The smell is stronger after they’ve been grooming

What to do (simple steps):

• Check the area for redness/irritation
• Keep the area clean (gentle wipe, don’t overdo it)
• If scooting/licking continues, it’s worth getting checked (anal glands can get painful).
  
  

2) Dental buildup (plaque/tartar + gum issues)

Bad breath is commonly linked to dental buildup and gum irritation. If the smell is constant (not just random bursts), teeth are a prime suspect.

Clues it’s dental:

• Yellow/brown tartar on teeth
• Red gums or gum bleeding
• Pawing at the mouth
• Drooling more than usual

What to do (at home):

• Start a simple “no stress” routine: chew time + dental support
• If your dog will tolerate it, brushing is ideal, but most dog parents struggle with it (you’re normal).

Check out our “No-brush dental chews guide” blog + Dental Chews collection here.

3) Diet (especially fish-based foods or rich treats)

Sometimes the answer is boring: something in their diet just… smells. Some foods, oils, and rich treats can change breath quickly.

Clues it’s diet:

• Fishy smell started after a new food/treat
• Poos changed at the same time
• The smell fades if you stop the new item

What to do:

• Pause any new foods/treats for a few days
• Reintroduce one at a time so you can identify the trigger
  
  

4) Tummy/digestive issues

Digestive issues can contribute to breath changes, including odd or fishy smells, especially if there’s reflux or ongoing stomach upset.

Clues:

• Burping, gurgly stomach, nausea
• Vomiting or diarrhoea
• Fishy breath + reduced appetite
  
  

5) Something medical (when you should take it seriously)

Sometimes bad breath can signal bigger issues (for example, dental disease or other underlying health conditions). If the smell is strong and persistent, or your dog seems unwell, it’s worth a vet check.

Go get help sooner if you notice:

• Lethargy, not eating, vomiting
• Blood from mouth, obvious pain
• Swelling around the face/jaw
• Breath smell that’s suddenly intense and doesn’t improve
  
  

What you can do today (simple, low-effort plan)

Step 1: Do the 30-second sniff + check

• Look at the teeth (any yellow/brown tartar?)
• Check gums (redness?)
• Quick bum check (is your dog licking/scooting?)
• Notice if it’s “random bursts” vs “always”
  
  

Step 2: Start a “chew routine” (especially if brushing is a battle)

Chewing can help mechanically reduce some plaque buildup for many dogs, and it’s a realistic routine most households can maintain.

Easy routine:

• 10–20 mins chew time a few times per week
• Supervise, and remove small swallowable ends

Check out Dental Chew Options Here!

Step 3: Don’t ignore the bum clues

If fishy breath comes with scooting/licking, treat it like a real issue, not a “gross dog thing.” Anal gland issues are common and fixable.

The Lenny’s Pup Shop take

Fishy breath is one of those gross dog-parent moments that usually has a simple cause. Start by checking bum habits + teeth + diet, then build a routine you can actually stick to (chew time counts).

If you want a low-effort habit: a consistent chew routine can support cleaner teeth for many dogs, without turning your life into a nightly toothbrush fight.