Cann Grain Free Tuna. Is it BAD for cats

I've been trying to switch to a grain free cat food because it is supposed to be better for them.  They are carnivores.  I went from Science Diet dry (told it is equal to Cat Chow) and Friskies, only the ones with gravy to Canidae grain free dry.  I've tried a LOT of grain free.  Wuerva BFF (they didn't like the Wuerva Chicken only the gravy), which is supposed to be one of the best but they only like the Tuna and Turkey and Tuna a Salmon.  Now I am researching that Tuna is not good for them because of the mercury in it.  I am so disappointed.  I finally found a food they will eat but I am concerned about the mercury in tuna.

Anyone have any info or experience with feeding Tuna to cats.

Thanks,

I don't have that much experience in feeding tuna because I took the advice and didn't feed that much tuna!

Fish in general is not recommended too often. Meaning once or twice a week is OK. The concerns are with the mercury that you mentioned but also because it can cause addiction and then kitty will refuse to eat other foods. Fish is also high in phosphorus, which can lead to UTIs. If you have male kitties UTIs can be life threatening. (It can be with females, too, but with males differences in anatomy make it much easier to become an emergency.)

Also, in general it is not good to feed only one protein or one brand of food. Rotating brands and proteins prevents cats from getting too fussy and reduces dependence on a single brand of food in case of a recall.

You can try putting some shaved bonito on other flavors in order to transition them to another flavor. Or try different textured foods (pate, shredded, chunked). In general, the ones with gravy are going to higher in carbs/lower in protein, so pates are the better choice nutritionally.