Three Reasons Why Cats Should Never Eat Tuna

Tuna is something that is often used in cat food but is a meat source that cats really should not have. First of all cats should never have tuna canned for people, but pet owners should additionally limit other tuna even when already in prepared cat foods.

Not only is tuna something cats would never normally be exposed to (it is a deep sea fish) but it can cause health problems for the cats who eat it. Learn why you should not feed tuna to your pet cat.

1. Tuna is High in Mercury

As a top ocean predator, tuna is generally quite high in mercury. Most fish do contain some mercury, and what happens is that small fish are eaten by bigger ones, and those fish are eaten by bigger ones, and so on, such that the mercury from all those fish accumulates in the top predators.

Tuna contains even more mercury than salmon. Different kinds of tuna have been found to have different amounts of mercury and the type used in cat food is rarely indicated so is probably not the best quality, (in fact it is probably the tuna rejected from human consumption), as such it should be highly suspected of containing large amounts of mercury.

Mercury poisoning can cause mood or behavioral problems and central nervous system problems in cats and it can be fatal.

2. Tuna Does Not Contain Taurine

Taurine is an important amino acid that cats require, it is found in most meats such as beef and chicken. Tuna fish does not have any taurine. If tuna is a major part of the cat’s diet the cat will not get enough taurine and suffer deficiency related problems such as loss of eyesight.

3. Oil and Onions

Although some foods are safe for humans to eat they may not be safe for all other animals, including cats. Onions and oil are good examples of this. As such when some foods are prepared or canned for human consumption they may not be good for cats.


When tuna is canned for people it may be canned in oil. When fed to cats the oil contributes to a problem where fatty lumps form under the cat’s skin. This is a painful condition know as steatitis, or yellow fat disease. It comes from the oil disturbing the cats ability to absorb Vitamin E, resulting in a deficiency.


Tuna fish that is canned in oil, or water, when canned for human consumption, often contains garlic or onion. While both are bad for cats, onions are particularly bad. Onions can lead to anemia, overtime this can be fatal, or at the very least can leave the cat weak and at risk for other health concerns.


Author’s cat

Why Do So Many Cat Foods Use Tuna?

You may be surprised to realize how little the pet food industry as a whole cares about the health of our pets.  Many poor quality ingredients are used in pet food.  The pet food industry is a great way to use waste products from the human food industry. The tuna industry can sell waste product that is not fit for human consumption to pet food companies (or for fertilizer). Additionally because tuna has an appealing smell to cats it encourages cats to eat an otherwise poor quality cat food, such as one that uses other cheap ingredients.

Just because cats like tuna, and most do, does not mean it should be fed to them. Tuna is often used to bait for trapping skunks or feral cats, it may be offered to a cat who is sick and refuses to eat; the strong smell means it works well for both situations. Overall, though, tuna should not be considered okay to use as a major part of a cat’s diet.

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