Dogs can eat tuna, but it should be offered in moderation due to concerns about mercury content and the nutritional balance of a dog's diet. Tuna can be a good source of protein and omega-3 fatty acids, which can benefit your dog's skin, coat, and overall health. However, the way tuna is prepared and served is crucial to avoid any health risks — small amounts of plain, cooked tuna on rare occasions is generally fine, but it shouldn't replace healthier, safer protein options formulated specifically for dogs.
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Nutritional Value
Tuna in correct amounts provides several nutritional benefits for dogs, including:
- Protein: high-quality protein supports muscle development and repair.
- Omega-3 fatty acids: promote healthy skin and a shiny coat, and can support heart health.
- Vitamins B3, B6, and B12: essential for energy production and maintaining healthy cells.
- Minerals: selenium, magnesium, and potassium, which support various bodily functions, including the immune system and muscle health.
| Nutrient | Value per 100g of tuna | Small dogs (1–10kg) daily requirement* | Medium dogs (11–26kg) daily requirement* | Large dogs (27kg+) daily requirement* |
| Calories | ~130 kcal | 200–400 kcal | 400–800 kcal | 800–1,600 kcal |
| Protein | ~28g | 25–50g | 50–75g | 75–100g |
| Fat | ~1g | 10–20g | 20–40g | 40–80g |
| Omega-3 fatty acids | ~0.2–0.5g | 0.1–1.5g | 1.5–2.5g | 2.5–3.5g |
| Vitamin B3 (Niacin) | ~8.3mg | 4–11mg | 11–15mg | 15–20mg |
| Vitamin B6 | ~0.5mg | 0.18–0.55mg | 0.55–1.1mg | 1.1–2.2mg |
| Vitamin B12 | ~2.5µg | 9–13µg | 13–20µg | 20–50µg |
| Selenium | ~92µg | 36–90µg | 90–120µg | 120–200µg |
*These daily requirements are rough estimates and will vary depending on the individual dog's health, lifestyle, and dietary needs. Always consult your veterinarian for personalised dietary advice.
Despite these benefits, tuna's mercury content is a concern, as high levels can lead to mercury poisoning in dogs over time.
Food Suitability
Tuna is suitable for dogs in small amounts. It's best served as an occasional treat rather than a regular part of their diet. Fresh or canned tuna in water (not oil) without any added salt or spices is the safest choice.
Feeding Instructions
When introducing tuna to your dog's diet, consider the following:
- Moderation: keep tuna as an occasional treat. For small dogs, a teaspoon is enough; medium to large dogs can have a tablespoon.
- Preparation: ensure the tuna is cooked (if fresh) and doesn't contain any added ingredients harmful to dogs.
- Canned tuna: choose tuna canned in water rather than oil, and ensure it has no added salt or spices. It's also worth checking the species — most standard supermarket canned tuna is skipjack ("light" or "chunk" tuna), which carries meaningfully lower mercury levels than albacore ("white") tuna, so it's the safer choice if you have a say in which tin you buy.
Risks
Feeding tuna to dogs comes with potential risks:
- Mercury poisoning: regular consumption of tuna can lead to mercury accumulation, which is toxic. Larger species like albacore tend to carry more mercury than skipjack, so being mindful of which type you're feeding — and how often — makes a real difference.
- Sodium content: canned tuna can contain high levels of sodium, which isn't suitable for dogs, particularly those with existing heart or kidney conditions.
- Allergies: some dogs may be allergic to fish, including tuna. Monitor your dog for any signs of a reaction.
Signs of Tuna-Related Illness
If you've given your dog tuna, watch for any of the following, and contact your vet immediately if you notice them:
- Excessive thirst or urination
- Lethargy or weakness
- Loss of coordination
- Vomiting or diarrhoea
- Tremors or seizures
- Hair loss
These can be signs of either sodium poisoning or mercury toxicity, both of which need prompt veterinary attention.
Allergies and Sensitivities
Watch for signs of an allergic reaction, including itching, swelling, gastrointestinal upset, or difficulty breathing. If you notice any of these symptoms, stop feeding tuna and consult your veterinarian.
A food allergy is rare — more common is a food intolerance, which is estimated to affect up to 10% of dogs. At My Pet Sensitivity, we offer a dog food intolerance test that can help give you peace of mind before feeding your dog new foods.
Alternatives to Tuna
If you're seeking alternatives to tuna for your dog, consider other fish or lean proteins that are lower in mercury and safe for canine consumption:
- Salmon: a great source of omega-3 fatty acids, but should always be cooked to avoid the risk of parasites.
- Sardines: low in mercury and high in omega-3 fatty acids — opt for those canned in water without added salt.
- Chicken: a lean protein that's generally safe for dogs when cooked and served without bones or seasoning.
FAQs
Can tuna cause mercury poisoning in dogs?
Yes, similar to humans, dogs can suffer from mercury poisoning if they consume too much tuna over time. It's crucial to limit tuna intake and consider safer alternatives.
How often can I feed my dog tuna?
Tuna should be an occasional treat rather than a regular part of your dog's diet. Once every few weeks is a general guideline, but less frequently is advisable for smaller dogs due to the higher risk of mercury accumulation.
Is fresh tuna safer for dogs than canned?
Not necessarily where mercury is concerned — that depends on the species and size of fish, not how it's prepared. Fresh, plain cooked tuna does avoid the added sodium found in most canned products, though.
Portion Sizes
When feeding tuna to your dog, follow these suggested portion sizes to keep it as a safe and enjoyable treat:
| Dog size | Suggested portion |
| Small | 1 teaspoon of cooked tuna |
| Medium | 1 tablespoon of cooked tuna |
| Large | 1–2 tablespoons of cooked tuna |
These portions are intended as occasional treats, not regular meal replacements. Always ensure the tuna is plain, cooked, and free from any bones or seasoning.
Tuna can be a nutritious treat for dogs, offering benefits like protein and omega-3 fatty acids. However, due to the risks associated with mercury content, it's important to offer tuna in moderation, following the recommended portion sizes for your dog's size. Always opt for plain, cooked tuna without added ingredients, and consider lower-mercury fish alternatives to diversify your dog's diet safely.
To provide you with technically accurate, evidence-based information, content on the My Pet Sensitivity blog is reviewed by medical professionals with veterinary expertise.
Related reading: What Human Foods Can Dogs Eat? · Can Dogs Eat Salmon? · Signs & Symptoms of Dog Food Intolerance and Allergies