Pond Design

Size, depth and volume 
You will have to consider what the koi environment needs when deciding the size, depth and volume of the pond.

Material used to construct the pond
There are typically 3 options – Concrete pond will use a pre-formed bowl. Large ponds are built by the South Eastern Asian countries using reinforced concrete whereas smaller ponds use pre-formed fiber glass.

Filter design or filtration systems
Filtration System is the most important aspect of a Koi pond. Some of the key considerations shall be

  • Build (custom designed in-ground filter) or Buy (commercially designed external filtration systems)
  • Location of your filter
  • Size of the filter
  • Bottom drains

The water quality depends heavily on the design of filtration system and also determines the health of your Koi A good filter system will also make pond maintenance easy.

This is often planned and selected together with the filtration system. If the filter is the “kidney” of the pond, the pumps are its “heart”. Selection of the right pumps is just as important as the filter design as it will affect the water flow rate, effectiveness of the filter system and workings of water features.

Aeration and water features 
All “living” organisms require oxygen to live. This also includes aquatic species. When the koi grows and multiplies, the demand for the oxygen also increases. Enriching oxygen at the bottom accelerates the microbes and leaves the debris. The biological filter requires oxygen and bacteria. The pond aeration allows excess of water during heavy rain.

Surface skimmer 
There is a way to remove floating debris from the water debris in every koi pond. A surface skimmer can be used to remove the dust oil, protein scum and small debris.

Bottom drains 
Bottom drains are important features of your pond used for easy maintenance.

Water plants
The size and shape of the pond is the factor that depends on whether you should include water plants. Once we know the types and species of water plants that are suitable for Koi pond,overall design and layout of your pond needs to be planned carefully.

The edging of your pond serves a few purposes:

  • Prevents Surface Water when it rains from entering your pond.
  • Aesthetics
  • Safety Barrier
  • A Suitable Platform for feeding and netting your Koi

NOTE: If your pond is an informal garden pond, the edging is important as you would want it to mix with the rest of the garden.

Platform or place 
It is good to consider where you would  feed or catch your Koi safely. Avoid protrusions (e.g. overflowing pipe or skimmer) or even water plants near the place where you intend to feed your Koi feeds in frenzy and knock themselves against such protrusions.

UV light filter 
UV light filter is useful to control bacteria or parasites, kill germs and sterilize the pond water.

Water supply 
Water lost through evaporation is one of the biggest concerns hence easy source of water supply must be provided. All you can do is build a water inlet pipe directly into the pond, or having a tap or faucet located next to the pond works the best.

Power source for pumps
The most effective way for maintaining pumps is to have multiple power sources, with individual circuit breakers. That way, a single pump failure would not knock out all the pumps and water circulation and aeration.

Koi’s environmental needs 
Japan where the koi originated from has many years of selective breeding leading to the development of various colorful varieties of Koi. If you are serious about Koi keeping, the Living Jewels must maintain good water quality at their peak condition.

Koi can grow up to 1 metre in length, but most Koi sold are young Koi and averages from 20 cm to about 50 cm. Koi need space to thrive and some Koi experts have claimed that the growth rate is proportional to the pond size.

Oxygen level 
Koi and bacteria needs oxygen in the biological filter. Dissolved Oxygen level of 8 mg/liter  in water is about 25 deg C.This is ideal at the saturation point.

NOTE: Plants (including algae) in the water also use oxygen at night.  During photosynthesis plants take in carbon dioxide and produce oxygen only in the day.

Temperature and Pond depth
Koi prefers temperatures below 28 degree Celsius. As,warmer water does not carry oxygen when compared to the cooler water. A minimum pond depth of 4ft and a proper shade on the pond will help maintain water cool.The depth of the pond should ideally be at least 1.2 meter or about 4 feet. Deeper pond is good for the Koi’s growth. But we have to be careful of the proportion of the depth verses the size of the pond. Although, a deeper pond would allow for greater pond volume per unit pond surface area.

pH level
A measure of the acidic or basic nature of a solution is called a pH level. Water with a lower PH level is termed as acidic while alkaline water would have higher pH.Low pH levels kill Koi and many other fishes. It is generally better to have pond water for Koi with slightly higher pH (7.4 is ideal. Not more  than 8.0).

Ammonia , nitrite  and nitrate 
Fish produces ammonia as a waste product. The bacteria in the filter breakes down ammonia to nitrite and then from nitrite to nitrate. Nitrate is relatively less harmful to Koi than ammonia or nitrite. A good biological filter system can be achieved when the ideal levels of ammonia, nitrate and nitrite are zero.