Can Cats Eat Tuna

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can cats eat tuna fish

Can cats eat tuna fish? Due to the wide variety of tuna in cat food that is easily available at stores, most cat owners presume that the answer to this is yes. However, this is not the case. Tuna flavored cat food is not the same as actual tuna.

can cats eat tuna fish

The Differences Between Feeding Your Cat Tuna and Tuna Flavored Cat Food

The companies that design cat food do so with great care so that the food fulfills all your cat’s nutritional requirements. It is designed in such a way that your cat receives the necessary quantity of protein but is not harmed by an excess amount of mercury or magnesium. Cat food that is specially formulated, and of a tuna foundation, is designed to include the tuna in a way that is not harmful to your cat.

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Tuna in itself does not provide your cat with all the nutrients she requires. You may not feed your cat a diet based solely on tuna fish.  Adding tuna as a treat, or as a meal when you are out of cat food, is safe, but only in moderation.  Tuna may be mixed into cat kibble, or offered in small bites, but only when proper cat food is also given. In order to make the cat food with tuna healthier, minerals, vitamins and taurine (an essential amino acid for your cat) are also added to it.  You as a cat owner may not be able to add these extra vitamins on your own which is why specially formulated tuna for cats is the best option to offer your kitty.

The tuna that is normally consumed by humans, on the other hand, is not suited to your cat’s digestive system. While your cat might be able to break down small quantities, feeding her large amounts can lead to numerous problems.  Many cat owners offer their tuna to cats without a second thought.  Cats have been associated with tuna for a long time, and cat owners may think they are doing their cats a favor by offering tuna. In some cases, offering tuna is safe.  Tuna that is clean, stored in water, and is fresh may be offered in a few bites.  You may not offer large amounts, or offer human made tuna often because your cat will be unable to digest this food the way cat food with tuna is digested.

Can Cats Eat Tuna – The Disadvantages


Feeding your cat a diet based solely on tuna can lead to malnutrition. It lacks important nutrients like iron, sodium, vitamins B and E, copper and calcium which are necessary to keep your cat healthy.  There are a great many vitamins your cat will benefit from by eating tuna, but only when tuna is a supplement, not the entire diet.

Thiamine deficiency

Tuna lacks the necessary minerals and vitamins when fed to your cat in great quantities. It can cause a thiamine deficiency. If your cat has such a vitamin B deficiency then she may show symptoms that include fits, appetite loss and in extreme situations death


Tuna also contains an enzyme called thiaminase, which prevents the B vitamin thiamine from being processed. This enzyme is present in both raw and canned tuna. Therefore, not only does tuna not contain the vitamin B thiamine, it also prevents the vitamin from being absorbed by your cat’s body when obtained from other sources.


Another important vitamin tuna lacks is the vitamin E. In addition to malnutrition, a lack of this vitamin can also cause a disease known as steatitis or yellow fat disease. Steatitis results in the swelling of the fat tissues in your cat’s body and can be diagnosed through symptoms such as:

  1. Weight loss
  2. Mental disturbance
  3. Stomach pains
  4. Loss of appetite
  5. Weakened of muscles
  6. Lack of coordination
  7. Rashes
  8. Loss of memory
  9. Worsened eyesight
  10. Sensitivity
  11. Fever

Mercury poisoning

Trace quantities of mercury can be found in almost every fish. As you go further up in the food chain, the quantity of mercury gradually increases. Tuna being further up than most fish in the food chain, tuna contains great quantities of mercury. When your cat eats large amounts of tuna regularly she also ingests a great quantity of mercury, eventually causing mercury poisoning.  Cats are adept to hunting and eating wild foods when undomesticated. A cat rarely comes across tuna in the wild and lacks the evolutionary ability to break down the meat and is not able to tolerate the levels of mercury either.

Mercury poisoning is a serious matter for your pet and is very dangerous.  Be sure to avoid poisoning your cat and research tuna before offering to your kitty.  Certain sizes and breeds of cats may be more susceptible to mercury poisoning than others.  You should speak to your vet in regards to offering human food to your cat, and s/he will be able to guide you on making the best choices for your pet.

Unsaturated fats

Tuna also contains large quantities of unsaturated fats. Unsaturated fats may be good for humans but a cat’s digestive system is not the same as a human’s. A great amount of unsaturated fats can be unhealthy for your cat.  Cats cannot digest fats the way humans do and the cat does not need fats in her diet coming from outside sources.  The necessary fats and calories derive from proper cat food, not from human food.  Fats from human food can lead to weight gain, obesity, and heart problems.


Tuna is rich in flavor and smells delicious. This can be dangerous when cats get addicted to the flavor and turns down any other kind of food you try to feed her. You should feed your cat tuna as an occasional treat instead of a main diet. If you make a habit of offering tuna to your cat, your cat will begin to disregard her proper food and will be at risk for malnutrition.


Eating fish can also cause allergies in some cats. If you do decide to feed your cat tuna, make sure to supervise her closely the first time so you can gauge if she is allergic to it. In case your cat is allergic, be sure to stop feeding her tuna immediately and in case of a severe reaction take her to the vet.


While cats in the wild might hunt for food and eat raw tuna, your pet is domesticated and tamed. Your cat cannot stomach the same food as her wild counterparts. Your cat might get stomach problems trying to digest the tuna.

Can Cats Eat Canned Tuna

Canned tuna often contains salt, oil and brine. Not to mention preservatives and flavorings; all these are extremely harmful for your cat’s health. Oil leads to a deficiency of the vitamin E and affects muscles. Salt consumption results in an imbalance of electrolytes in your cat.

However, there is tuna available that is packed in water and does not contain salt. When buying tuna to feed your cat make sure you check the labels for the ingredients.


Can cats eat tuna? Yes, they can. Tuna provides your cat with necessary amino acids, as well as, omega 3 fatty acids. Both of these are important nutrients that keep the cat healthy. Therefore, tuna in moderate amounts, as a treat, does not harm your cat and is quite safe.


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