My cat is 14 and has had some health troubles for a few years, off and on. We've mostly been able to manage it. But it has often resulted in needing to adjust his diet - either because what he is eating is making him sick, because he needs special food with specific stuff, or because he just flat decides he isn't going to eat something anymore (the fun one).
A little over a month ago he got a new problem after being good for awhile where he was throwing up a huge amount. After some checkups and lab work the vet was able to prescribe us a huge batch of medication to hopefully deal with the issue (various inflammation markers present, low levels of certain parameters, etc. - not really important here). As he started getting more sick he stopped eating as much, which isn't surprising. Now he's getting better, but eating even less and we can't quite figure out what to do.
He is definitely hungry and wants food, just not what we give him. The wet food he used to eat he has decided is out. We went through multiple new flavors, types, and brands and he tries them then decides he doesn't want them. We found one type of dry food he'll eat enough of to not completely starve, but not as much as he needs. Also after he got bladder stones years ago we switched away from dry food (or to prescription urinary dry food) on the vets recommendation, so a pure dry food (or even mostly dry food) diet isn't ideal if at all avoidable.
So backstory out of the way, to keep him from actively starving to death we gave him some tuna a few times over the last few weeks. I KNOW canned tuna isn't good for cats and can't be a long term thing, please don't spend time commenting to tell me that. He'll eat the tuna like a madman. But we try tuna based wet cat food and he almost doesn't touch it. Doesn't seem to matter the brand or the style (pate, chunks, etc).
Has anyone run into this situation (not just not eating, but the will eat tuna, won't touch tuna cat food) and if so did they find something the cat would eat? What is it about the normal tuna that the cat food doesn't give? Is there a cat food that will give him that?