The one goal that every koi keeper have in common is to avoid headache and really turn Koi into a spiritual entertainment. We need to pay attention to making a good designed koi pond system because without it, the koi will have many problem in the future. Understand  Koi pond design is a very first step to join this hobby and enjoy it for many more years to come.

1. Mud pond:

The number of people that have mud or natural pond is very small, except for fish farms or a small number of people with the right conditions (land and water source). Having mud pond can seem simple, but going deep is quite complicated. 

For example, you can have a mud pond with a water surface area of 1000m2  (11000 SF) or more.  You can drop 50 tosai and nisai of all kinds. You just need to make sure that this pond has been sanitized, feed the fish 2-3 times a day, and you can add live shrimp to the pond to provide more food . The fresh water need to flow constant to the pond on one side and overflow out from the other side (Filter is not needed). This seems simple but high risk. The cleaning and disinfection of the mud pond and finding a well water source to supply the pond depending on the season is also something you have to prepare from the beginning.

2. Koi pond:

Most koi keeper will adopt this approach. Raising koi in cement tanks, glass tanks, liner, plastic tanks, composite tanks …. because it is more compact than the mud pond, and also easier to control. You can look at the koi anytime  and enjoy them much more.

Since everything is only relative (the space and budget), usually  depth of the koi pond is usually 3-5 feet deep (depending on the conditions of your land, and it’s up to you whether you want to raise a professional koi or keep them for fun. Also, it depend on whether you want to raise koi small and medium size or you want to raise koi from 80cm or more …).

To keep koi healthy, not sick, and grow fast (1-2-3 years old), you need build a pond about 3000-5000 gallons of water and about 4-5 ‘deep. With that amount of water, we can feed your fish 2-3% of the fish’s weight each day without worrying about the water getting dirty and having to change the water continuously. Each week, we need to change 20-30% of the water in the pond or flow through 3-5% per day (24/7)


Koi pond filter system contain 3 principles:

  1. Water Inlet: Bottom drain and skimmer
  2. Filtration system: Mechanical Filter, Bio Filters
  3. Water outlet: Waterfall or jets (TPRs)

 Note: More details can be found on KOI POND FILTRATION 


The next important part of the koi pond is the flow of water and the current.
You should carefully calculate the volume of the pond(not including the filtration volume). Usually in a small pond system, the total water flow in 1 hour need to be 2-3 times of the pond volume.

For example, if your pond is 3000 gallon, the water flow should be from 6000-9000 gallon per hr. From there, you can calculate the total number of water pumps needed to create this flow (note 25-30% reduction of capacity written on the pump). If your tank is small (less than 3000 gallons) then the flow rate should be 3-4 times the volume of the tank which will be more advantageous for your koi.

The water pipe to the Pond is sized from 3 “-4” depending on how big or small your pond is. Pipe size depends on pump capacity, pump capacity depends on tank volume. They all have to work together to optimize the use of the space, and equipment. 

If you use jets (TPRs), you should pay attention. Avoid using small sized pipes as the current in the pond will be very poor. Jet 120 degrees is best because the water will push close to the lake wall. Each jet is only effective about 4-5 feet so you should have enough jet to push water all around the pond.


4 ”: 5000 GPH
3 ”: 2500 GPH
2 ”: 1200 GPH

It is also depends on how many 90-45-22.5 connection that you use, the more connections, the water flow in the pimp will decrease.

If your pond flow is above 3000 gallons you should have 2 bottom Drains, each 4” bottom drain is Great. With two of 4″ bottom drains, you can run Max 10k GPH. That would be 3 times water per hour. Add one more 4 ” Skimmer is the best. The water flow to the settling chamber/ RDF will be calm, and will reduce the dissolution of manure in the settling lake / drum.



The dissolved oxygen is very important in koi pond design. It helps your Koi digest better, absorb nutrients better, accelerate the process of toxic gas emissions, help the microbiota grow well and stable. Therefore, you should have at least 02 aerator (one for the pond and one for the filter (If shower is not used).

Koi need oxygen in water so it is extremely necessary to equip a battery or a backup generator to run the gas generator in the event of a power outage.


This is just a brief summary of what a basic koi pond looks like for you to refer to. Of course, it is not rigid and can flexibly change depending on the circumstances and environment, topography.

Wish with these information, you’ll create a great designed koi pond system.


    Bottom Drain. Helix Skimmer. Helix Moving Bed Waterfall filter Aqua RDF Aqua Bio Aqua Shower

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