Koi Pond or a Water Garden, Why Not Have Both?

Most Koi keepers will tell you that Koi and water plants do not go well together. There is some truth in it as Koi eats plants. Some serious Koi lovers will not include any plants in their Koi pond. They would keep their pond layout simple. Their main or only focus is on their expensive, show-grade Koi and they would not want sunken plant pots that the Koi may bump into or fertilisers and rotting plant waste that may contaminate the pond water. Although water plants do help remove nitrates, increase oxygenation and provide shade, the serious Koi lovers’ ponds will have other means to take care of these.

However, most pond keepers, including myself, would like to have some greenery in their Koi ponds so as to have a pond that looks natural and able to blend with the overall garden. The best compromise is to include a separate water garden that contains other fishes and aquatic plants, that is physically separated from the main Koi pond that contains only Koi, but sharing the same filtration system to reduce cost. It is important to decide this as you design your pond and plan the layout. A water garden is usually shallower than the Koi pond which is ideally more than 4 feet (1.2 meters) in depth. Another solution is to include a narrow and shallow shelf (of about 1 to 2 feet deep) at the edge of the Koi pond where water plants may be grown. In any case, the selection of suitable plants for your Koi pond is important as Koi eats plants.

Water plants can be broadly classified into 4 categories:

• Marginals or Bog pond plants that naturally grow on the edge of a pond or are slightly submerged. These are the best plants to include in a Koi pond if your aims are to beautify the pond, blend the pond with the overall garden and have ease of maintenance and growing. I plant these in pots and place them, half submerged, in the shallower part of the pond. The aim is to keep the soil and roots moist but with the main parts of the plants above the water surface.
• Submerged plants or Oxygenators that provide a pond (or fish tank) with oxygen through the natural process of photosynthesis. These plants would be nice in an aquarium or fish tank but not recommended for a Koi pond.  They will not survive in a Koi pond. Koi eats plants!
• Floating plants or Floaters that floats on the water surface. They multiply rapidly and help to keep algae and water temperatures down. However, they are not suitable for a pond with Koi. Koi tends to eats the roots and shred the leaves. In fact, they love the roots more than the leaves. So, floaters are best grown in a water garden that contains only small fishes.
• Water lilies and lotus that grow submerged under water but with floating leaves and/or leaves that grows above the water. Water lilies need regular fertilisations to keep them blooming daily, so growing them a pot that can be easily accessible is best. The pots are placed in water of about 24 inches depth. They are best kept in still water, away from any venturi pipes or waterfall that will cause ripples or disturbance at the water surface. Large Koi tends to dig at the soil around the plants. A top layer of pebbles or stones large enough to cover and protect the soil is needed in the pot. They are best grown in a water garden that contains only small Koi/fishes or in a water garden that is separated from the main Koi pond containing large Koi.

In summary, if you want both Koi and plants in the same pond, stick to marginals or bogs plants. If you want to include water lilies and lotus, find some means to protect them.