I know I always worry, when I read cat stories, that it is a precursor to the cat being deceased, so let me start by saying, my cat is alive. (Knock wood!)
Anyway, a little background. When I adopted my cat from the shelter, I asked for the food they had been feeding her, and then got some of that, figuring we could explore other options later.
She was a kitten, so we were doing dry food, and wet food at night. At some point Kayla stopped eating the wet food. Like there was excitement and interest when I served it, but it would be uneaten, so I stopped serving it.
When time came to change to adult food, I bought adult food in the same brand.
This remained uneaten for two days. At that point, I went to the store, and examined the adult food - this particular brand helpfully puts the shapes on the bag - found an adult brand that was the same shape as kitten, also bought a bag of kitten, and served it. The adult food was deemed acceptable.
I did decide at this point that my cat had been poisoned in a former life.
Over the years, every once in a while, Kayla would get excited when I did something like pop open a can of chickpeas, and I would go buy one can of wet food to see if things had changed. She would sniff it and then not eat it.
Well, this year at the vet checkup, they recommended wet food. Older cats are more likely to need hydration, so I understood why it was being recommended, but explained that she had been resistant to eating it. They offered me a thing to sprinkle on the food.
So, I procured a few kinds of wet food. I served one - when it got sniffed but not eaten, I sprinkled on the stuff, and it did get eaten.
Well, the good news is that Kayla will now eat wet food without the extra topping. She has decided on the one type (available in four flavors) that she will consume. Of particular note, if the word healthy, weight, or hairball appear anywhere on there she is not interested.
Also, Kayla and I have negotiated what time wet food occurs. Some days she has expressed concerns that I might not recall.
But apparently old(er) cats can learn to accept new things.