What Are Tuna Flakes?

Maggie J. Hall

Tuna flakes are shavings from dehydrated, fermented, and smoked tuna. Cat owners often serve the fish flakes as a special treat or add them to cat food. Sometimes referred to generically as bonito flakes, the product may also be manufactured from the bonito fish, which is an ocean species related to tuna. Though cats savor the aroma and flavor of the fish, pets may develop health problems from consistent diets containing tuna. Tuna flakes are part of traditional Japanese cuisine and are frequently used as a garnish on hot dishes.

Some cat owners give their pets tuna flakes as an occasional treat.
Some cat owners give their pets tuna flakes as an occasional treat.

Once caught and returned to shore, the skipjack tuna undergoes a lengthy process before becoming tuna flakes. Processors generally remove the fins, head and organs of the fish and cut the body into fillets. These are arranged in a basket and placed in boiling water for about one hour. The water temperature remains constant at 194 degrees Fahrenheit (90 degrees Celsius). Following this cooking process, workers remove the bones, fat and scales from the tender fish.

Some species of tuna -- which provides the popular canned, dried, and fresh fish -- can grow more than six feet long and weigh hundreds of pounds.
Some species of tuna -- which provides the popular canned, dried, and fresh fish -- can grow more than six feet long and weigh hundreds of pounds.

The tuna undergoes a smoking process one or more times. The fillets are exposed to the smoke of castanopsis, oak, or pasania wood. After smoking for the desired length of time, processors shave the surface of the fish, removing dirt, tar and other debris. The fish are dehydrated further by placing the fillets directly into sunlight. Manufacturers extract additional moisture from the tuna by spraying them with mold spores.

The mold naturally depletes the fish of moisture as it grows. After substantial growth occurs, plant employees shave the surface, removing the mold. Workers generally repeat this process until there is no longer any moisture to support mold growth. At this point, the fillets have a consistency of hard wood. At roughly one-fifth its original size, the tuna now contains approximately 2% moisture.

Machines then remove layer after layer of paper-thin shavings from the tuna. Manufacturers package the tuna flakes and sell them all over the world. Pet owners generally find tuna flakes in specialty stores selling pet food and other products. The nutritional value of tuna flakes includes a minimum of 75% protein, 3% fat and 1% fiber. Some products may also be fortified with taurine, an essential cat nutrient.

Provided as an occasional treat, tuna flakes are relatively harmless. Diets consisting largely of tuna lack vitamins E and K. The absence of vitamin E causes a condition known as steatitis, or yellow fat disease. A lack of vitamin K prevents normal blood clotting. Tuna also contains elevated levels of magnesium which can contribute to bladder or kidney stones.

Tuna may contribute to kidney stones.
Tuna may contribute to kidney stones.

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Discussion Comments


I love tuna flakes, I think they're the most versatile food ever. You can put it in soups, in stir-fries and any dish with fish to add flavor and texture. It tastes great!

The other day, I made fish cakes with it. I basically just mixed the tuna flakes with some mashed potatoes and spices. Then I just put it on a baking sheet and cooked it in the oven. It came out nice and crispy on the outside and soft on the inside. It was delicious and it was as if I used fresh fish.

For most una flakes recipes, I used canned tuna flakes, but for soups, I use dried tuna flakes that are sold in the bag. It's sort of like bacon bits.


@fify-- I give my cats tuna flakes as a snack occasionally. One of my cats likes it on top of her food for a little bit of tasty crunch but I refuse to give it to her on a normal basis.

I personally prefer tuna flakes for cats. The reason is because the other kind usually has salt added to it which is not good for cats. And the canned variety might be packed in oil, which again is not good.

The version for cats has none of those additives and also has taurine and sometimes other vitamins like the article said. I do know that some health and organic stores carry tuna flakes without the unnecessary additives, oil and salt. If you can get your hands on that kind, I don't see anything wrong with feeding it to the cat.

Still, don't overdo it. Tuna flakes are usually made from skipjack tuna which has a moderate amount of mercury. So feeding it too often will be bad for the cat in the long term. Just give it once a while as a prize treat.


Does anyone feed their cat tuna flakes regularly? Do you buy one that is especially made for cats, or the kind for human consumption?

I saw the tuna flakes at a pet store and immediately thought that this could be a good snack for my cat. I wanted to read reviews about it first though so I didn't purchase it. A couple of days later, I was at the Asian grocery and saw tuna flakes there too. This kind is for human consumption but it looks exactly the same as the kind for cats. I also checked the ingredients and didn't see any additives, it's just dried tuna flakes. The price is more affordable too.

Do you think it's okay if I feed this to my cat?

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