I'm sorry to hear about Gatsby. Hopefully he'll recover quickly and you won't have any more blockage problems with him. Did your vet tell you if he had crystals in his urine?

My Storm blocked 2 times and before the second time he was already eating a special veterinary diet. He had to have PU surgery because he had scar tissue and they couldn't even get a cather in him the second time. He was then put on Royal Canin Urinary S/O canned and dry food for quite a while but he'd still have UTI's some times. His urine would also some times be very concentrated and would some times still have some struvite crystals in it.

Now all of my cats are on a grain free diet and they eat Innova Evo dry and canned food. Storm gets 2 helpings of canned food mixed with some water every day and I know that this is helping him a lot. He hasn't had any problems since. A bigger plus is that all of my cats love this food. I'll keep Gatsby in my thoughts and prayers.