Food that makes koi grow fat:

1. Animal feed. Animal feed is Koi's favorite food, and it is the most nutritious feed. Common ones are fish worms, mealworms, etc.

2. Pasta. Regular pasta is fine, such as steamed buns. You can also use some puffed food such as popcorn to increase nutrition for koi.

3. Milk powder. When raising koi fry, you can feed them some milk powder, which is very rich in protein.

4. Microscopic algae. Microalgae can also be used as koi fish food, which can provide koi with necessary trace elements and increase the body's resistance. Moreover, koi itself particularly likes to eat microalgae.

5. Vegetables. Koi also like to eat green vegetables. The high fiber content in vegetables can promote the digestion of koi and make it easier to absorb other foods.