Creating a Koi Pond in Your Garden
A koi pond can be an excellent accent to your garden. It is not that difficult to build. However, koi are long lived so once you get some they are yours for a long time. Make sure you are willing to commit to then for their lifespan.
The first thing to do is pick an area for the pond. Koi ponds for the average hobbyist should be 23 and 25 feet long by 12 to 13 feet wide and 3 to 4 feet deep. However, koi can grow to three feet in length so making the pond deeper in one area will be appreciated by the fish. Mark the area for the pond with stakes until you can see the exact outline for the pond. Make sure that is what you want the pond to be before you start digging.
Dig the dirt out of your pond outline. Pile it nearby because you will need it later. Make sure the outline is dug out to the depth you want it. Shallow ponds may freeze in cold weather and the koi will need enough unfrozen water under the ice to make it through the winter. On the flip side, in hot climates you need enough water in the pond to keep it from getting too hot for the koi.
Koi produce lots of waste so you need to have two bottom drains to suck out that waste and clean the water before returning it to the pond. You want the drains to be gravity fed so debris does not stir up and make the water foul. You will need the two bottom drains to each go to a separate settling box so that the waste is efficiently removed. The water then goes to another area where the smaller waste particles are mechanically filtered out. The water then goes to a biological filter where good bacteria eat any debris that might be left. Finally, the water is now clean and is returned to the koi pond over a waterfall or similar arrangement.
Insert the pond liner in the pond. Make sure that there is a two feet overlap that sits outside the pond. When you have the liner the way you want it, use the dirt and rocks you dug out of the hole to cover the liner that is on the grass. It is important to cover all the liner that is out of the pond so water will not get under the liner and cause a problem.
You should mark the locations of the two bottom drains with a marker and then cut out the holes. Use an aquarium safe adhesive to glue the liner to the bottom drains and to glue the collar that keeps the liner out of the way.
Install a pump (out of the pond but close to it) that will circulate the water back over the waterfall and into the koi pond. At this point, all of your filter system and pump is hooked up and ready to go. Do not turn the system on yet.
Fill the pond at this point with water and let it sit over night. Turn on the pump and filtration system and see if it works. If so, great. If not, go over the directions and try again until everything works.
Now you are going to have to decide if you are going to have vegetation in and around the pond. Koi eat plants and can make a mess of your well placed vegetation. Koi will do just fine eating only the rations you feed them. It is nice to have vegetation around the pond. The easiest way to do that is to leave a shelf around the rim of the pond and about six inches under the surface of the water. You can take plants such as lotus and other water plants and put them in pots, then place the pots out of site on the ledge. This will protect your plants and make it easy to remove and replace any that cause a problem. Be careful of plants such as lotus that will take over the pond if allowed to do so. Keeping in a pot makes sure it does not cover the surface of the pond and make it hard to see your koi.
Call your water company and ask if they use chloramines to get rid of bacteria. If so, you will need to add a neutralizer to make sure the chemical does not poison your fish and water plants. You will also need to add a product that removes chlorine from the water before you add the fish.
A pond of the dimensions this article talks about will comfortably hold fifteen koi. It would probably hold more, but the pond will start to look crowded and the fish will be packed in like sardines.
If you live in a cold climate, you will want to heat the pond during the winter. You can purchase readymade pond heaters. These are not the horse trough heaters but something more substantial. There are also plans on the internet for building a koi pond heater. The fish are happier and grow faster with a heater so it is a good idea to get one. It also lets you control the temperature of the water and keep it just right for the koi.
Your routine maintenance for the koi pond consists of replacing twenty-five percent of the water in the pond with new water in the summer and ten percent in the winter per week. Make sure you have treated the new water to remove chloramines and chlorine. You will also need to empty the filters once a month or so. Finally, you will need to test for ammonia and nitrates and pH once a week. The test for ammonia and nitrates should show zero present while the pH should be around 7.5.