Debbie, I'm so sorry to hear that Robin has calcium oxalate crystals. I'm still currently feeding all of my cats Innova Evo dry which does have some fish in it but it's not the main ingredient. I also feed them a lot of the canned Innova Evo in 95% Venison and 95% Duck. They used to like the 95% Chicken/Turkey but now that don't for some reason. I've also started feeding them Nature's Variety Instinct Rabbit and Lamb in the cans. The all seem to love the Rabbit which of course is the most expensive. I always mix some water with it so they get extra moisture and I add a bit more water to Storm's. So far it's been helping Storm with his urinary problems. I hope that you'll find a great food for both Robin and CJ. They do make a lot more grain free food than they used to but many of them do have fish in them. Good luck.