Herring is a fantastic source of omega-3 fatty acids and protein for dogs, but like many fish, it can carry environmental toxins such as mercury, PCBs, and histamines (especially if not fresh). You don’t have to cut it out entirely, you just need to be smart about how you serve it. Here is a practical, owner-to-owner guide to minimizing herring toxins in your dog’s diet, so you can keep mealtime both healthy and safe.
1. Choose the Right Type of Herring
Not all herring is created equal. Wild-caught Atlantic or Pacific herring generally has lower toxin levels than farmed or large predator fish. Avoid herring from known polluted waters, and always look for fish labeled as “wild-caught” and “sustainably sourced.” Smaller herring (like sardine-sized) accumulate fewer toxins because they are lower on the food chain. If you have a multi-pet household, you might also be curious about how different breeds interact, for example, are Maine Coon cats good with dogs? That is a separate topic, but it shows how we think about all your pets’ wellbeing.
2. Cook It Properly to Reduce Toxins
Cooking herring can reduce certain toxins like histamines and bacteria, but it does not remove heavy metals. Steaming or baking at a moderate temperature (around 350°F) until the flesh is opaque is best. Avoid frying, which can add unhealthy fats. Never feed raw herring unless it has been frozen to kill parasites, and even then, raw fish carries a higher risk of histamine-related reactions. A good rule: cook it, then let it cool completely before serving.
If your dog is a picky eater, try flaking cooked herring over their regular kibble. The strong smell is often irresistible, and you only need a small amount to add nutrients without overloading on potential toxins.
3. Watch Portion Size and Frequency
Herring should be an occasional treat, not a daily staple. For a 50-pound dog, one small herring fillet (about 1-2 ounces) once or twice a week is plenty. Smaller dogs need even less. Overfeeding any fish can lead to mercury buildup over time. If you are also managing a large breed like a Bernese Mountain Dog, you might already be careful with their diet, and you can also check do Bernese Mountain Dogs shed a lot to stay on top of their overall care.
4. Consider Herring Oil Supplements as a Safer Alternative
High-quality, molecularly distilled herring oil supplements are often safer than whole fish because the distillation process removes heavy metals and PCBs. Look for products that are third-party tested and list the source (e.g., wild-caught North Atlantic herring). The oil gives you the omega-3 benefits without the toxin risks of the fish flesh. Always check the dosage on the bottle and consult your vet before starting any supplement.
“A little herring goes a long way, treat it like a special reward, not a main course.”
5. Know the Signs of Histamine Poisoning (Scombroid)
Herring that has not been stored properly can develop high histamine levels, causing scombroid poisoning. Symptoms in dogs include vomiting, diarrhea, drooling, reddened skin, and panting. If you notice these within an hour of feeding herring, contact your vet immediately. To prevent this, always buy fresh or frozen herring from a trusted source, keep it refrigerated, and never serve fish that smells off or has a metallic taste. For owners of breeds prone to drooling, like Bernese Mountain Dogs, it is extra important to distinguish normal drool from a reaction, so read up on why does my Bernese Mountain Dog drool so much to know what is normal.
6. When in Doubt, Ask Your Vet
Every dog is different. Dogs with kidney issues, allergies, or those on certain medications may be more sensitive to fish toxins. Before adding herring to your dog’s diet, especially if they have health concerns, have a quick chat with your veterinarian. They can recommend the safest serving size and frequency based on your dog’s weight, age, and overall health. Your vet can also help you decide between whole fish and a supplement.
