My cat will go out to eat grass when it vomits hairballs (a must). The usual recipes include: chicken breasts (blanch them in boiling water), lamb liver and lamb lungs (cooked), in bulk Cat food, water. Occasionally a sparrow feeds it. It has been eight years and I have grown very fat. But my cat doesn’t eat fish, I don’t know why, he only eats canned sardines in tomato sauce (mixed with rice). It seems that every cat has different tastes. Grandma’s cat eats fish. It is best not to let it eat rats. First, it is likely to cause infectious diseases. Second, it may eat poisonous rats and die.