Fish Food - yay or nay?

Hi everyone! I own 4 cats - 12yr old black DLH rescue - Merlin, 10yr old black one-eyed rescue DMH - Rasputin, 9yr old snow Bengal - Gandalf, & 8yr old brown Bengal - Weasley. I also usually have a foster cat present. Everyone gets along well. Merlin had a number of issues when I got him - grade 3 heart murmur, chronic anemia, allergies. Put him on a high protein food (which the bengals are supposed to be on too anyway) and he's still a spry kitty with no relapses. Weasley got a severe skin reaction a few years ago on his neck. Vet did scrapings, looked under a uv light, took blood, did everything but we never ascertained whst caused it. She suspected an allergy to chicken an/or grain. My kitties have always been on grain free but we were using grain litter so we switched to clay litter and chicken free food and he's also been fine. Other two kitties present no issues.

Which brings me to my question. Try finding a grain free food that also has no chicken in it. Not easy. Even the venison or duck or beef or rabbit foods often have chicken. So that leaves fish food. I've heard various rumors that fish based foods can cause issues in cats from hyperthyroidism to urinary issues. I'm wondering if anyone has experienced this and if anyone has any opinions on fish based foods. I only feed my cats the highest quality - evo, hound y Gatos, Merrick,Fromm. They get free fed dry (everyone is perfect weight) and a can of wet at night. I've been able to find some game foods that don't have chickens or grain in them but not everyone here is in concensus that they like that food. Rasputin pretty much turns his nose up at all wet food.

So - anyone have any issues / opinions on fish based foods for cats? Anyone had their cat develop hyperthyroidism or other complications? Much appreciated.

(Oh and I do know human canned tuna is bad for them. Just referring to cat food made from fish specifically)

Thanks!

If you are in the US, the Wild Calling line of wet food that aren't chicken doesn't have chicken in them. My cat tends to throw up more frequently on primarily fish flavors, so I don't know about them, but I feed WC for non-chicken flavors.

You don't have to feed fish. You can try Nature's Variety Instinct canned and Pride by Instinct canned. Most of their varieties do not contain chicken, except for the chicken flavors, of course. It is grain, wheat, and soy free also. Halo Spot's Stew lamb is another winner in my house and again--no chicken or grains.

I don't fish is too bad if it's just fed a couple of times a week. I personally don't feed it though, because I'm paranoid about mercury and other toxins.