In that case, I'm not the one to help you. Besides strongly suggesting that you avoid any seafood in his diet, I'm pretty much in the dark on this. Sorry about that.Vet has no knowledge of a raw diet. That is why I asked here. She told me to look into it.I used to have a tomcat with this problem, Nimbus. It seemed that anything with fish in it also made the crystals more likely. Our vet did surgery on him, to shorten his urinary tract so that it would be less painful for him, but that didn't exactly cure it. You can do a lot keeping him on the correct diet. Follow your vet's advice on this. If you'd like to put Felix back on raw, ask your vet for ways to do it that won't aggravate the problem.
Margret
My best suggestion, besides asking the more knowledgeable people here, is that you do a Google search on "causes of <exact diagnosis>" and "which minerals cause urinary crystals in cats" followed by "dietary sources of <mineral from last search> for cats." The last two together should give you a great deal of information about which foods you need to avoid feeding him. They should also tell you why he wasn't having trouble before he was taken off of the raw diet, and why he began having trouble when he was put on kibble. Chances are that you were already feeding him exactly the right things.
Once you've done as much research as possible, proceed slowly. Keep him on the prescription food, but start adding in the raw foods one at a time, leaving a month or two in between new foods. That way, if he starts having trouble again, you'll know exactly which food caused it.
How are you currently keeping him from poaching the other cats' food?
Margret