Can Cats Have Tuna Packed In Water

Many cat owners reach for a can of tuna as a quick treat or to entice a finicky eater. Tuna packed in water is often considered a healthier choice than oil or brine, but is it truly safe for your feline companion? The short answer is yes, but only in strict moderation and with certain precautions. This article provides a clinically informed overview of feeding tuna packed in water to cats, including benefits, risks, and practical feeding guidelines.

Quick Q&A: Common Questions

Question: How much tuna packed in water can I give my cat?

Answer: A small amount, about one tablespoon, once or twice a week is generally safe for an average adult cat. Too much tuna can lead to mercury accumulation, thiamine deficiency, or nutritional imbalances. Always consult your vet for advice specific to your cat, especially if they have underlying health conditions.

Is Tuna Packed in Water Safe for Cats?

Tuna packed in water is the safest option among canned tunas for cats. Unlike tuna packed in oil (which adds unnecessary calories and fats) or brine (which contains high levels of sodium), water-packed tuna provides lean protein without added salt or oils. However, it should never replace a complete and balanced cat diet.

Nutritional Benefits and Concerns

Tuna is rich in high-quality protein and omega-3 fatty acids, which can support skin, coat, and joint health. But it is also very low in taurine, an essential amino acid that cats must obtain from their diet. A treat of tuna a few times a week won‘t cause a taurine deficiency, but relying on it as a staple can lead to serious health problems such as dilated cardiomyopathy or vision loss.

Additionally, tuna contains thiaminase, an enzyme that breaks down thiamine (vitamin B1). Chronic feeding of raw or improperly processed tuna can cause thiamine deficiency, leading to neurological issues like ataxia, seizures, and lethargy. Canned tuna that is heat-processed (as most commercial tuna is) has reduced thiaminase activity, but the risk is not zero if consumed in large amounts.

Comparison with Other Packing Liquids

• Water: Lowest in calories and sodium. Best choice for occasional treats.
• Oil: Adds excess fat, which can cause weight gain or pancreatitis in predisposed cats. Some cats may also develop loose stools.
• Brine: High sodium content (often 200–400 mg per serving) can stress a cat’s kidneys and worsen hypertension or heart disease.

The American Veterinary Medical Association (AVMA) and the British Small Animal Veterinary Association (BSAVA) both advise against feeding fish that is not part of a nutritionally balanced cat food. Tuna packed in water is acceptable as a small treat, but it should never make up more than 10% of a cat‘s daily caloric intake.

Health Risks to Consider

Feeding tuna packed in water, even sparingly, carries several potential risks that every cat owner should understand.

Mercury Accumulation

Tuna is a predatory fish that accumulates mercury in its tissues. Larger species like albacore (white) tuna have higher mercury levels than skipjack (light) tuna. Chronic consumption of mercury can cause heavy metal toxicity in cats, resulting in neurological signs such as tremors, incoordination, and behavioural changes. The European Medicines Agency (EMA) recommends limiting fish intake for small pets due to this risk.

Thiamine Deficiency

While cooking reduces thiaminase activity, no canned tuna is completely free of the enzyme. Feeding tuna every day can deplete thiamine stores over weeks or months. Signs of deficiency include loss of appetite, vomiting, dilated pupils, and in severe cases, head tilting or seizures. If you notice any of these symptoms, stop feeding tuna and contact your veterinarian immediately.

Sodium and Kidney Health

Water-packed tuna still contains some naturally occurring sodium. For cats with chronic kidney disease (CKD), hypertension, or heart disease, even small amounts of sodium can be problematic. The American Animal Hospital Association (AAHA) strongly recommends avoiding all human fish products for cats with these conditions.

Unbalanced Diet and Obesity

Tuna is palatable but nutritionally incomplete. A cat that fills up on tuna may refuse their regular food, leading to deficiencies in taurine, vitamin A, arachidonic acid, and other essential nutrients. Over time, this can cause obesity if the tuna contributes extra calories without balanced nutrition.

Home Care and Feeding Guidelines

If you decide to give your cat tuna packed in water, follow these simple guidelines to keep them safe.

How to Serve Tuna Packed in Water

Choose tuna labelled as “light” or “skipjack” to minimise mercury. Drain the water completely and offer only the flaked tuna. Do not add any seasonings, salt, or oils. Offer it as a standalone treat or mix a small amount into your cat‘s regular food. Avoid feeding tuna that is past its expiration date or that has an off odour.

How Much and How Often

For an average 4–5 kg (9–11 lb) cat, one tablespoon (about 15 grams) once or twice a week is sufficient. A piece the size of your thumbnail is a good rule of thumb. Never feed a whole can. Keep a food diary to ensure tuna does not exceed 10% of your cat’s daily calories.

The Canadian Veterinary Medical Association (CVMA) echoes these guidelines, noting that fish treats should be given sparingly and only in addition to a complete commercial diet.

When to Consult Your Veterinarian

Speak to your veterinarian before offering tuna if your cat has:

• Chronic kidney, heart, or liver disease
• A history of urinary tract crystals or stones
• Pancreatitis or gastrointestinal sensitivity
• Food allergies or sensitivities

Also, seek veterinary care if your cat shows any signs of thiamine deficiency, mercury toxicity, or digestive upset after eating tuna. A vet can perform blood tests to check for deficiencies or electrolyte imbalances.

Prevention and Long-Term Dietary Considerations

The best way to ensure your cat receives balanced nutrition is to feed a high-quality commercial cat food that meets Association of American Feed Control Officials (AAFCO) or European Pet Food Industry Federation (FEDIAF) standards. These diets are formulated to provide all essential nutrients, including taurine, arachidonic acid, and preformed vitamin A.

If your cat loves the taste of tuna, consider using a veterinary-approved commercial cat treat that contains tuna as an ingredient. These treats are tested to be safe and complete. Alternatively, a small piece of cooked, unseasoned fish such as salmon or cod (without bones) can be a lower-mercury alternative.

In summary, tuna packed in water can be a safe occasional treat for most healthy cats, provided it is given in very small amounts and not as a dietary staple. Always prioritise a balanced commercial diet and consult your veterinarian for personalised advice. By keeping these clinical principles in mind, you can enjoy sharing a savory morsel with your cat without compromising their health.