Can Cats Eat Raw Tuna Steak?

You bought a beautiful tuna steak for dinner and your cat is extremely interested. But is it safe to share a piece of raw tuna with your cat? The answer is more complicated than you'd think. Cats are carnivores, and wild cats do eat raw fish—so raw tuna seems natural. But there's a big difference between a small fish caught fresh and a tuna steak from the grocery store. Raw tuna comes with risks that most cat owners don't know about: parasites, bacteria, and an enzyme that destroys essential vitamins. Even sushi-grade tuna isn't completely safe for cats.

Raw tuna is not toxic in the way chocolate or onions are toxic, but it's not safe either. The biggest concerns are parasites, bacteria, and thiaminase. Tuna can carry parasites like roundworms and tapeworms that survive in raw fish. Freezing kills some parasites, which is why sushi-grade fish is frozen first—but freezing doesn't kill everything, and it definitely doesn't kill bacteria like salmonella. The third problem is thiaminase, an enzyme in raw tuna that destroys thiamine (vitamin B1). Cats fed raw tuna regularly can develop thiamine deficiency, which affects the nervous system. A tiny piece once in a great while probably won't cause problems. But raw tuna shouldn't be a regular treat.

The logic makes sense on the surface. Cats are obligate carnivores, and wild cats eat raw meat all the time. If you're making sushi or sashimi at home, it seems wasteful not to share with your cat. Plus, cats go crazy for the smell of raw fish. But there's a huge difference between a wild cat eating a freshly caught fish and a domestic cat eating grocery store tuna. Wild cats eat their prey immediately—parasites don't have time to multiply. Grocery store tuna might have been sitting for days, giving bacteria time to grow. And wild cats eat a variety of prey, so they don't get the thiaminase overload that comes from eating tuna regularly.

Not all raw tuna is equally risky. Quality and preparation matter.

Raw tuna has three major problems for cats. First, parasites. Tuna can harbor roundworms, tapeworms, and other parasites that infect cats. Freezing kills some of these, but not all. Second, bacteria. Raw fish can carry salmonella, listeria, and other bacteria that cause food poisoning. Cats have shorter digestive tracts than humans, which gives them some protection, but they're not immune. Third, and this is the one most people don't know about: thiaminase. Raw tuna contains an enzyme that breaks down thiamine (vitamin B1) in the cat's body. Cats fed raw tuna regularly can develop thiamine deficiency, which causes neurological problems like loss of balance, seizures, and even death in severe cases. Cooking destroys thiaminase, which is why cooked tuna is safer.

The risks increase with frequency and the amount fed.

Sushi-grade tuna is safer than regular raw tuna, but it's not completely safe. 'Sushi-grade' means the fish has been frozen at very low temperatures to kill parasites—usually at -4°F for seven days or -31°F for 15 hours. This kills most parasites, which makes it safer for humans. But it doesn't kill all bacteria, and it doesn't do anything about thiaminase. Sushi-grade tuna is fresher and higher quality than regular tuna, which reduces some risks. But if you're feeding your cat sushi-grade tuna raw, you're still exposing them to bacteria and thiaminase. The safest option is to cook it, even if it's sushi-grade.

If you want to give your cat tuna, cook it. Lightly seared tuna steak—plain, no oil, no seasonings—is much safer than raw. Cooking kills parasites and bacteria, and it destroys thiaminase. Your cat will still love the taste. If you're set on feeding raw fish, stick to smaller fish like sardines, which have less mercury and lower parasite risk. Better yet, use commercial cat food that includes tuna—it's formulated to be nutritionally balanced and safe. If you want to give your cat a special treat, there are freeze-dried raw fish treats made specifically for cats that have been processed to reduce risk.

No. Kittens are more vulnerable to parasites and bacteria than adult cats. Their immune systems are still developing, and their bodies are smaller, so any contamination affects them more severely.

If your cat ate a small amount of raw tuna, they're probably fine. But watch for symptoms over the next 24-48 hours.

Absolutely not. Daily raw tuna is dangerous for multiple reasons. Thiaminase will cause thiamine deficiency within weeks. Mercury will accumulate in your cat's body. Parasites and bacteria exposure increases with every feeding. Tuna also lacks taurine, an essential amino acid cats need daily—tuna-only diets lead to heart disease. Even if the tuna is sushi-grade and your cat seems fine at first, daily raw tuna will cause serious health problems. Thiamine deficiency symptoms include loss of balance, head tilting, seizures, and even death. This isn't theoretical—it's documented in cats fed all-fish diets.

No. Sushi-grade means it's been frozen to kill parasites, which makes it safer than regular raw tuna. But sushi-grade doesn't mean bacteria-free, and it doesn't remove thiaminase. The freezing process kills parasites like roundworms, but bacteria like salmonella can survive freezing just fine. And thiaminase is an enzyme that's naturally present in raw tuna—freezing doesn't deactivate it. Only cooking does. So even with sushi-grade tuna, you're still taking risks with bacteria and vitamin deficiency. It's safer than regular raw tuna, but it's not risk-free.

Cooked tuna is significantly safer than raw tuna. Cooking kills parasites, destroys harmful bacteria, and deactivates thiaminase. A lightly seared tuna steak—plain, with no salt, oil, or seasonings—gives your cat the taste they love without the risks. You don't need to cook it well-done; even a quick sear on the outside is enough to kill surface bacteria and reduce thiaminase activity. Some cat owners argue that raw is more 'natural,' but cats in the wild eat freshly killed prey, not grocery store fish that's been sitting for days. And even wild cats face parasite infections from raw prey—domestic cats just have access to veterinary care when problems arise.