If you want to add eye-catching designs to your landscape, koi ponds are one of your best options. These ponds can attract birds and butterflies which are a good sight to see but the problem is they also invite predators like cats, raccoons, dogs and some birds that love to eat koi.

A good architect would design a pond with natural barriers against these predators to prevent them from reaching the edges and feast on koi fish.

Tips for Designing Koi Ponds

A sight for sore eyes! There is a certain peace and tranquility that most people feel when they see koi fish swimming gracefully through the water.  This is why koi fish ponds have been a part of our modern-day architectural design. Koi has captured the hearts of hobbyists since ancient times. They started off in China and moved on to Japan where the art of breeding and designing koi ponds have reached unequaled popularity.


Koi fish are also known as Nishikigoi do not grow naturally in the wild. In the 1800s, the Chinese introduced carp to Japan. Japanese farmers had carp for food during the winter season and they were ordinary black carp back then. The rice farmers noticed that some offsprings had blotches of color and set them aside as pets. The black-colored ones they continued to eat and it was a staple on the dinner table.

They started breeding their “pets” to try and bring out more colored fish. Colored carp was first seen in 1843  and three breeds namely Asagi, Bekko, and Sarasa were identified. When the 20th century came, the Japanese become more passionate about breeding koi. Colored carp collecting is now spreading like wildfire all over the world. More and more hobbyists are collecting koi, breeding them and building ponds.

The history of pond building, on the other hand, did not turn out as we expect. Many koi fish did not survive in their new habitat due to poor air and water quality. The good news is advances in koi pond designs have been made in the last decade and the mortality rate for koi has been reduced to a more tolerable level.

Common Problems with Design

Designing a landscape with a koi pond was not taught in universities and many of the principles have been learned from hobbyist’s experience. Trial and error is the name of the game and it’s no surprise that faulty designs are widespread.The bad news is, faulty designs are passed on from one builder to another. Solving problems will come with pond renovation once mistakes are noticed.

Here are some of the common pitfalls in koi pond building:

  • Poor filter system design
  • Designing a pond without waterproofing and steel reinforcements resulting in constant pond leakage
  • Building a pond like a swimming pool with sharp-angled corners where water can’t circulate
  • Having structures that have sharp edges that can harm koi skin
  • Building a pond that is too shallow or narrow for the koi to swim
  • Situating the pond directly under sunlight which creates a hostile environment for koi
  • Placing aquatic plants in the pond like lilies and lotuses which are not suited due to salt being added to the water on a regular basis. Koi fish would also eat the plants so it wouldn’t be a practical addition
  • Lack of knowledge among newbies that koi are high-maintenance pets

Principles in Pond Design

The type and price of your koi are major factors in pond design. Koi prices range from $15 to $140,000. If you are a newbie who just wants ordinary koi in your pond or a passionate collector who intends to collect and breed the best koi fish. Your needs will dictate how your pond will be designed to fulfill the needs of your koi keeping.

Pond Filtration

If you want your koi to remain healthy and vibrant, investing in a good filtration system is essential. Choose a filter that would function well given the design of your pond.

There are filter types that require no maintenance but there are some components that need to be present in a good filtration system.

Bottom drains help make pond cleaning and maintenance easier for hobbyists. They are usually made from pipes that are partially covered at the bottom of your koi pond where pond water exits and moves to your filter system. Skimmers keep your pond surface clean by sucking any floating debris your pond may have and deliver them to the filtration system. Mechanical filters are your first line of defense as they collect large debris like leaves, excess food and fish waste. Filter brushes trap them and keep them off your pond. The next filter is a biological type which removes harmful toxins from your water using good bacteria.

Ultraviolet light

These lamps are submerged to make pond water clear. They breakdown algae that would make your pond color green. Bacteria levels are also controlled by the UV light.

Pond Pump

Pumps are one of the hardest workers in your system. They move water to the bottom drains into your filtration system and then drive the water back into the pond through a fountain or waterfall. They work non-stop to keep your water clean.


Oxygen levels in your pond should always be at an optimal level. Fish breathe by extracting oxygen from the water. Aeration pumps blow air into diffusers to maintain oxygen in your pond. 

Temperature Control

Koi will flourish in water temperatures of 25 degrees C. Showers or chillers are added to your pond especially during the summertime when temperatures can soar. 

Water Quality

A koi pond is different from a swimming pool that is static so designs should be different. Your pond is a living habitat where the laws of nature is applied. 

The goal in pond design is to duplicate the ecosystem where koi can thrive. While black carp can tolerate many types of water conditions in the wild, their koi descendants are kept in a pond where conditions are artificial compared to the outdoors. Clarity is only one aspect of your koi pond that you should maintain when it comes to water.

You need to keep the water temperature at an ideal level of 25 degrees C. Koi can’t tolerate high levels of toxins in pond water. Look out for high levels of ammonia, nitrites, and nitrates. If you notice that your koi has stopped growing and their colors are no longer vibrant, chances are you have high levels of toxins in pond water. Not doing anything can prove fatal to your prized pets

As a serious hobbyist, it is mandatory to change 10% of pond water daily. Filter systems can only go so far in keeping your water clean. Freshwater is always better than filtered water.

Take note that chlorine is harmful to koi fish. It can burn their gills and kill them. Buying a dechlorinator is a good idea before you fill your pond with new koi. You can also wait a week for the chlorine to disappear if you have the time.

Ideal Dimensions for Your Pond 

The ideal depth of a koi pond is 3 feet with a surface area of 16 square meters as the minimum size. You will have 20 tons of water when you choose these minimum dimensions and you can take care of 10 koi fish in these conditions. Serious breeders need to apply the rule of one koi per two tons of water so that they can grow big.

For owners who want to keep smaller koi in larger numbers, a 20-ton pond can sustain 40 smaller breeds of koi.

Why Koi Ponds are the Best compared to Aquariums

Compared to other fish, koi are beautiful to observe when viewed from above. This makes a pond design the best option than an aquarium. Koi patterns appear on the upper side of the fish. It is very relaxing to watch koi fish swim gracefully around the pond, architecture and pond design can make that happen.

Can Koi live with other fish?

As the name implies, a koi pond is designed for keeping koi fish only. Some owners prefer to keep other fish alongside their koi and two types that can co-exist with them are the Sabao and Tamasaba goldfish.

Stay away from carnivorous fish like arowana and arapaima if you don’t want your koi to end up as fish food for these predators.

Koi Pond Final Thoughts

We now know the importance of having the right design for your koi pond. Don’t be afraid to invest in a professional designer that has experience in designing koi ponds that have proven to work.

It may cost you more if you go the trial and error route so keep mistakes to a minimum by investing in a good pond design from the start. Don’t believe in the idea that one can design a maintenance-free koi pond. If you don’t have the time to maintain your pond there are companies that provide pond maintenance services for you at a minimal cost.

Leave A Comment

Your email address will not be published. Required fields are marked *