Does anyone else have a cat that is allergic to fish and dairy products?

Absolutely. Many cats have allergies to certain things in cat food! My eldest, who's been with my mother for 17 years is allergic to most cat foods. The way she found out which one was okay was by trying every single one she could find. Dry cat foods tend to have grain or corn, and sometimes that alone is enough for an allergic reaction. But many newer dried cat foods contain one meat- sometimes it's lamb, or chicken. Try those, being mindful to look for fish meal, a common additive. Sometimes it's the dyes in the food! You can never tell until you've tries them. Sometimes even foods that appear not to have allergens in them do. So as I said, read every can and every label, and try them out, one at a time. You'll soon find one that your cat can tolerate. ***If all else fails, and your cat needs food, boil chicken and make some rice. Grind it into a stiff paste and feed that to your cat. At least he'll get some untainted protein. I've done this for ailing cats and it works well.*** Just remember that they also need taurine, and that can only be found in vitamins or "cat gravy" vitamin liquid. Sometimes the vitamins themselves have allergens, so you'll have to try them out as well. Good luck! Eventually you'll find something. My Mom did, and she's pickier than the cat!