3 Answers

For a short time I imagine but koi can grow to 10" or more quickly.

How to properly raise koi:

Instructions
1
Place Koi in a well aerated and filtered pond at least 20 inches deep. You need to purchase a pond that is specially made to house Koi. The pond should be placed in a shaded area in order to keep the water cool.

2
Feed your fish daily. Koi need to be fed twice during the summer months and only once a day during the winter.

3
Clean your pond often. If you notice any dirt or debris in the pond, remove it with a net. You also need to put in fresh water monthly.

4
Purchase a water test kit. Koi need to be kept in healthy water conditions. To ensure the quality of their water, you should test the pH and ammonia levels on a monthly basis.

5
Use Dylox in the water every 3 months. This solution will kill any parasites in the water that can cause harm to the Koi.

Read more: How to Raise Koi | eHow http://www.ehow.com/how_2066400_raise-koi.html#ixzz2V1hDFbGB

Fish grow to the size of their container.........