What kind of plant do you use for a pregnant Koi fish to lay her eggs?

For a pregnant Koi fish to lay her eggs, you can use aquatic plants such as spawning mops, water Sprite, or hornwort. These plants provide a suitable substrate for the eggs to adhere to and offer shelter for the fry once they hatch. Additionally, floating plants like water lilies can create a calm environment that encourages spawning. It's important to ensure that the plants are healthy and free from pesticides or chemicals.