· 8 min read

Can Dogs Eat Swordfish? What Pet Parents Need to Know

You’re standing at the stove, searing a thick swordfish steak. The kitchen fills with a savory, oceanic aroma, and out of the corner of your eye, you spot your dog: tail thumping, nose twitching, those big, pleading eyes locked on your plate. “Just a bite?” they seem to beg. It’s a common scenario for pet parents—we want to share the foods we love with our furry friends. But before you slide that morsel across the table, there’s a critical question: can dogs eat swordfish?

In this post, we’ll dive into the details: the potential benefits (if any), the very real risks, safer alternatives, and expert advice to help you make the best choice for your pup. Let’s get started.

can dogs eat swordfish

Table of Contents

Can Dogs Eat Swordfish? The Short Answer

Let’s cut to the chase: Swordfish is not technically toxic to dogs, but it’s far from a safe or recommended treat. While it contains some nutrients dogs need, the risks—especially high mercury levels—outweigh the benefits for most pups. In fact, many veterinarians advise avoiding swordfish altogether.

If you’re looking to share fish with your dog, there are far safer options (we’ll cover those later!). But first, let’s understand what swordfish is and why it’s problematic.

What Is Swordfish, Anyway?

Swordfish (Xiphias gladius) is a large, predatory fish found in tropical and temperate oceans worldwide. Known for its long, sword-like bill (which it uses to stun prey), it’s a popular choice in human cuisine for its firm, mild-flavored flesh.

But here’s the catch: swordfish are apex predators, meaning they sit at the top of the food chain. Like other large, long-lived fish (think shark, marlin, or tilefish), they accumulate high levels of mercury in their bodies over time. This is because mercury, a toxic heavy metal, enters the ocean through industrial pollution and builds up in fish as they eat smaller, mercury-contaminated prey.

For humans, the FDA and EPA recommend limiting swordfish consumption—especially for pregnant women, young children, and those with health conditions. For dogs, whose bodies are smaller and more sensitive to toxins, the risks are even greater.

Potential Benefits of Swordfish for Dogs (If Any)

Before we dive into the risks, let’s acknowledge that swordfish, like most fish, does contain some nutrients that are theoretically beneficial for dogs. However, these benefits are minimal compared to the dangers, and they can be found in safer fish.

1. High-Quality Protein

Swordfish is rich in lean protein, which is essential for dogs’ muscle growth, tissue repair, and overall energy. Protein also supports healthy skin, coat, and immune function.

2. Omega-3 Fatty Acids

Fish like swordfish contain omega-3 fatty acids (EPA and DHA), which are linked to reduced inflammation, healthier skin and coat, improved joint health, and even cognitive benefits in dogs.

3. Vitamins and Minerals

Swordfish provides small amounts of B vitamins (B12, niacin), selenium (an antioxidant), and potassium (important for heart and muscle function).

But here’s the problem: These nutrients are not unique to swordfish. Safer fish (like salmon or sardines) offer the same (or more!) benefits without the mercury risk. So why take chances?

The Risks of Feeding Swordfish to Dogs: Why It’s Not Ideal

Now, let’s get to the serious stuff: the risks of feeding swordfish to your dog. These dangers make swordfish a poor choice for most pups—even in small amounts.

1. Mercury Poisoning: The Biggest Concern

Mercury is a neurotoxin that damages the brain, kidneys, and nervous system. Because swordfish are large and long-lived, they accumulate high levels of mercury. According to the FDA, swordfish contains an average of 0.995 parts per million (ppm) of mercury—far higher than the 0.1 ppm threshold considered “low” for fish.

Dogs are more vulnerable to mercury toxicity than humans because of their smaller size. Even a small serving of swordfish could push their mercury intake over safe limits, especially if fed regularly.

Symptoms of mercury poisoning in dogs include:

  • Lethargy or weakness
  • Loss of appetite
  • Tremors or seizures
  • Coordination problems (ataxia)
  • Excessive drooling
  • Kidney damage (over time)

Chronic low-level mercury exposure can lead to long-term neurological damage, which may be irreversible.

2. Choking Hazards

Swordfish has a firm texture, and if not properly trimmed, it can pose a choking risk—especially for small dogs or those who gulp their food. Large chunks or bones (though swordfish bones are less common than in smaller fish) can get stuck in your dog’s throat or digestive tract.

3. Seasonings and Preparation Dangers

Most swordfish served to humans is cooked with seasonings like garlic, onion, butter, salt, or lemon. Garlic and onion are toxic to dogs, even in small amounts, as they damage red blood cells. Excess salt can cause sodium ion poisoning (symptoms: vomiting, diarrhea, seizures), and butter adds unnecessary fat, which can lead to pancreatitis.

4. Parasites and Bacteria in Raw Swordfish

Some pet parents feed raw fish to their dogs, but raw swordfish carries risks. It may contain parasites (like anisakis) that cause gastrointestinal upset, or bacteria (like salmonella or listeria) that can make your dog (and you!) sick. Cooking reduces these risks, but it doesn’t eliminate the mercury problem.

How Much Swordfish Can Dogs Eat? (If You Still Want To)

The short answer: Veterinarians generally recommend avoiding swordfish entirely. There’s no “safe” amount because mercury accumulates in the body over time. Even occasional small bites can add up, especially for small dogs, puppies, senior dogs, or those with kidney or liver issues.

If your dog accidentally eats a tiny piece of plain, cooked swordfish (no seasonings, no bones), monitor them for symptoms like vomiting, diarrhea, or lethargy. Call your vet if you notice anything unusual.

But if you’re tempted to share swordfish on purpose? Don’t. The risks far outweigh any potential benefits.

Healthier Fish Alternatives for Dogs

The good news: There are plenty of fish that are safe, nutritious, and delicious for dogs. These options offer the same protein, omega-3s, and vitamins as swordfish—without the mercury risk. Here are our top picks:

1. Salmon

Why it’s great: Salmon is a gold standard for dogs. It’s rich in omega-3s (more than swordfish!), low in mercury, and packed with protein. It’s also easy to find fresh, frozen, or canned (look for no-salt-added).
How to serve: Cooked (to kill parasites) and boneless. Avoid smoked salmon (high in salt) or salmon with seasonings.

2. Sardines

Why they’re great: Sardines are small, short-lived fish, so they’re very low in mercury. They’re also affordable and loaded with nutrients: protein, omega-3s, calcium (if fed with bones), and vitamin D.
How to serve: Canned sardines in water (no salt, no oil). Drain them and mash them up, or serve whole (the tiny bones are soft and safe for dogs to digest).

3. Atlantic Mackerel

Why it’s great: Atlantic mackerel (not king mackerel!) is low in mercury and high in omega-3s. It has a stronger flavor than salmon, so it’s a hit with dogs who love fishy tastes.
How to serve: Cooked, boneless, and unseasoned. Avoid mackerel packed in oil (too fatty).

4. Cod

Why it’s great: Cod is mild-flavored, making it ideal for picky dogs. It’s low in fat, high in protein, and contains B vitamins and selenium.
How to serve: Cooked, flaked, and mixed into your dog’s kibble. No bones, no seasonings.

5. Haddock

Why it’s great: Similar to cod, haddock is a lean, low-mercury fish with a mild taste. It’s a good source of protein and B vitamins.
How to serve: Baked or boiled, boneless, and plain.

FAQ: Your Swordfish and Dog Questions Answered

Q: Is swordfish toxic to dogs?

A: No, swordfish isn’t technically toxic, but it’s high in mercury, which can cause serious health issues (like neurological damage) over time.

Q: My dog ate a bite of my swordfish steak. Should I panic?

A: Probably not, but monitor them closely for 24–48 hours. If they show symptoms like lethargy, vomiting, or tremors, contact your vet. One small bite is unlikely to cause immediate harm, but regular feeding is dangerous.

Q: Can puppies eat swordfish?

A: Puppies have developing nervous systems and smaller bodies, so they’re even more sensitive to mercury. Never feed swordfish to puppies.

Q: What about canned swordfish? Is that safer?

A: No. Canned swordfish often has added salt, which is bad for dogs, and it still contains high mercury levels.

Q: Are there any dogs that can safely eat swordfish?

A: Very large dogs (like Great Danes) might tolerate tiny, occasional bites better than small dogs, but even then, there’s no good reason to feed swordfish. Safer fish are always a better choice.

Conclusion: Prioritizing Your Dog’s Health

At the end of the day, sharing food with our dogs is one of the joys of pet parenthood. But when it comes to swordfish, the risks—especially mercury poisoning—make it a food best left off the menu.

Instead of swordfish, opt for safer, nutrient-dense fish like salmon, sardines, or mackerel. These options give your dog all the benefits of fish (protein, omega-3s, vitamins) without the danger.

As always, if you’re unsure about introducing new foods to your dog’s diet, consult your veterinarian. They can help you choose options that fit your dog’s age, size, and health needs.

Your pup’s tail will wag just as hard for a bite of cooked salmon as it would for swordfish—maybe even more, once they taste how delicious (and safe!) it is. Here’s to happy, healthy mealtimes for your furry friend!

References

  • American Kennel Club (AKC). “Can Dogs Eat Fish? Benefits and Risks.” akc.org
  • U.S. Food and Drug Administration (FDA). “Fish: What Pregnant Women and Parents Should Know.” fda.gov
  • ASPCA. “Toxic and Non-Toxic Food for Dogs.” aspca.org
  • PetMD. “Mercury Poisoning in Dogs.” petmd.com
  • World Health Organization (WHO). “Mercury and Health.” who.int
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