Things You'll Need
- Measuring tape
- Rod
- Pump
- Filter
Instructions
Build your pond correctly so you can stock it the way you want. Koi are large fish and need adequate space. To keep koi, you need at least 1,000 gallons of water capacity in your pond. Add 100 gallons more for each additional koi. It's best to start with a pond this big, to accommodate the fish when they're fully grown.
Measure your water capacity. If you don't know the gallon size of the pond, measure the square footage. Measure the length and width using a measuring tape, and use a rod to measure the depth of the water.
Purchase a pump and filter system at a local pond or aquarium supply shop. Speak with an employee, and purchase a system that has a filtering volume of at least 33 percent of your pond's capacity. For a 1,000-gallon pond get a pump and filter system that holds at least 330 gallons of water. For a large pond, choose a system that also has a high flow rate, and passes water through the filter quickly.
Set up your pump and filter system in a corner of the pond, per the directions, and turn it on. Allow the system to run for at least 24 hours before you put fish into the water.