Koi carp won't starve to death if they are not fed for a month, but it will affect their health. Koi carp have relatively strong hunger tolerance and can survive for a long time without being fed. Specifically, koi carp can survive for 15 to 30 days without food, and the exact time depends on their living environment and their own physical condition. Koi carp raised in an aquarium usually can only last for about 15 days because they have less access to food. However, in a natural environment such as a pond, koi carp can go without food for 30 days.
However, not feeding koi carp for a long time will have a negative impact on their health. Insufficient nutrition will lead to slow growth, a decline in immunity, and may even cause diseases. Therefore, it is recommended to feed koi carp regularly and ensure the water quality and oxygen supply for them.