Tuna

Tuna supplies complete protein and omega-3 fats, and cats tend to like it, so it’s common in wet cat foods. Where a food is mostly tuna, check the label says it’s complete and balanced: fish alone isn’t.

Fish was one of the two most reported food allergens in cats in a review of the research. Tuna is also a large, long-lived fish, which can build up more mercury than small fish, so variety is a reasonable idea. Ask your veterinarian about your own cat.