Building a Koi Pond

Building a koi pond can be a great way to spend the weekend, and the whole family can join in. You could hire someone to do it, you could even buy a manufactured pond kit, but what fun would that be?

The first and most important step is to plan ahead and make sure you have all the necessary tools and supplies on hand.

How many fish do you want to support in the pond?
Where do you want to build the pond?
What shape do you want the pond?
How deep will you make the pond?
What types of plants do you want in and around the pond? Do they have sunlight requirements?
What size pump, sterilizer and filtration system do you need for this pond?
Do you need to plan ahead for any fancy features like waterfalls or fountains?

Also, if you value your life you should call your utility companies the week before you plan to dig to have them mark the locations of underground cables, in most areas they will do this for no charge.

Bigger is Better

A heron sneaks a fishy snack.

The biggest mistake people make is building a pond too small. Bigger ponds are more stable, easier to maintain, and produce healthier fish.

The minimum recommended depth is 4 feet, however 6 feet deep would be better, and 8 feet deep or more would be best. There are many predators who love an easy fish dinner, and adding some deep holes gives them the best chance to evade hungry raccoons, cats, herons, kingfishers, and other fish loving predators. Deep water will also provide your koi cool water to relax in on those hot summer days.

The geometry of your pond's footprint is entirely up to you, but bigger is better for healthy and happy koi. A rule of thumb is to plan an absolute minimum of 100 gallons for each full size koi, and that is very crowded.

Choosing a Location

The aesthetics of your yard and your personal taste will largely dictate where you decide to build your pond, but there are a few basic pointers you should follow.

Choose a location that is not in the direct sunlight all day. If you want to grow lillies or other plants choose a location that gets 4-6 hours of direct sunlight per day.
Avoid building directly under large trees or you may find yourself spending more time than you'd like cleaning leaves and branches out of the pond, particularly in the fall.
Choose a location where runoff from rain will not flow into the pond bringing with it fertilizer, chemicals, and debris.

Before You Dig

Use stakes or rope to mark the perimeter of your pond, and dig out the pond into the desired shape and depth. Be creative with the depth, creating shallow areas, shelves, and deep holes for your fish.