If you do a quick online search, you'll find a variety of opinions about whether or not tuna is safe for cats to eat. However, the general expert consensus is that canned tuna can be a healthy snack for cats — but only in small amounts, as an infrequent treat.
Tuna provides cats with essential nutrients such as high-quality protein and omega-3 fatty acids, which helps them maintain healthy skin, coat and joints. Tuna also contains Vitamin D, which plays an essential role in regulating calcium uptake in their bodies, leading to strong bones.
But it's important to remember that not all types of tuna are created equal. Some kinds may contain higher levels of mercury than others — the light and skipjack varieties tend to contain less mercury than albacore. Feeding your cat too much tuna — especially the type of tuna that's high in mercury — can lead to mercury toxicity. (Again, moderation is key.)
You should also avoid feeding your cat canned tuna that has oil, added salt or other flavorings, as these additives can be unhealthy for them. And only feed your cat cooked tuna. Raw fish of any kind can contain harmful, illness-causing bacteria.
The bottom line: Feeding your cat human-grade canned tuna, packed in fresh water rather than oil or salted water, shouldn't pose any significant health risks if you only do it once or twice a week. Just make sure this doesn't become their primary food source (or anything close to it).
As always, before introducing a new food item into your pet's diet, consult with your veterinarian first! If your cat eats tuna (or any food) and is showing signs of illness such as lethargy, diarrhea, or vomiting, reach out to your veterinarian immediately. If your pet requires veterinary care due to something they ate, pet insurance can help cover the cost of treatment.