My meow doesn't eat cat food, but only likes to eat fish for cooking. What should I do?

However, he has never eaten that kind of cat food since he was a child. He drank some milk at the full moon, and then he ate Miao Xianbao. Besides, his stool is a little abnormal. Meow meow used to be dry, and its poop was a little wet. He always gets his paws and fur dirty, so he has to take a bath. My kittens used to eat cat food, but this one didn't like it, and only ate fish rice. . . It doesn't know if it is full, and it keeps eating. And when summer comes, the fish rice is likely to turn sour soon. Attached is a cat without integrity. I don't seem to know whether it's my sister or my brother. . . But does it feel like a female cat? !