The Coast News Group
Local Roots

Building Koi ponds

My newest client put me through the paces recently and insisted that I build him a new Koi pond and waterfall.
Although I am no stranger to water features or ponds, making a living habitat that works for large, expensive fish seemed a bit daunting. So, I enlisted a little bit of Internet research and incorporated the advice of aquarist Stephen Marshall, owner of Advanced Aquatics.
What I learned bolstered my intrinsic understandings and even opened my eyes a bit to some interesting facts about raising Koi in a controlled aquatic setting.
Being a good landscape contractor means more than throwing in plants around new hard-scape.
Biology and science tell us that if you want longevity in your plantings and want to master what really happens behind the scenes of a beautiful ecology, you’ve also got to understand how it all works.
Ponds and Koi are very susceptible to environmental change. Temperature alone can create conditions that will wipe out your fish if you continue to feed them as temperatures drop precipitously or rise unpredictably.
Optimum feeding temperatures for Koi are between 60 degrees and 80 degrees. Temperatures below 50 slow the digestive processes of these fish and will kill them if they are over fed.
Most Koi in optimum temperatures should be fed once a day. Once the fish get used to their surroundings, they should be able to consume the amount of food given them at any one setting in two minutes leaving nothing behind. Food left over or food taking more than two minutes to be consumed will be unhealthy to the fish and the aquatic environment.
Expensive Koi are typically more colorful and require more expensive food to retain their interesting and vibrant colors. This special food is rife with hormones that control and enrich the pigmentation of the fish making them more beautiful. Don’t ask me how.
Koi come in many varieties; some are similar to goldfish, others are expensive and difficult to find and purchase. Each has it’s own personality and individual traits. If a fish is still hungry after feeding or is not fed during the cold winter months, it will feed on the algae in the pond or insects that fall into the water feature on a regular basis.
It was recommended to me that after construction of the pond or waterfall, the new water should be allowed to stand alone without fish for two to three days before complete evacuation and refilling. The reason for this depends upon the amount of lime and concrete constituent chemicals that will leach into the water from the newly constructed pond or concrete liner that encapsulates the new water feature.
Ponds and their inhabitants need an ecological balance to maintain a status quo amid their happy campers. Too low or high a pH will result in catastrophe and dead fish. This is very similar to your run of the mill swimming pool. In a living ecosystem like a pond, the more decaying debris in the water like leaves or uneaten food the lower the pH will become. Simply changing out 20 percent to 30 percent of the water will raise the pH to balance and help control the growth of algae in the pond.
This changing of the water is very important if your water feature is overcrowded. A rule of thumb dictates that one large Koi fish should inhabit every 10 square feet of surface water. Most homeowners install many more fish than this because they find it more interesting and attractive. Even smaller fish in great numbers can be problematic because of the nitrites and waste products they expel.
Bio Waterfalls and a built-in ultraviolet light are very important in treating water full of these problematic nitrites. Beneficial nitrite fixing bacteria help change the waste products of the fish to usable nitrates, (fertilizer) that plants can consume and flourish from. The ultraviolet light eliminates some algae and other organic pathology.
This is why aquatic plants are so important to our earth and waterways in that they compete with the water clouding algae for nutrients and balance the entire ecosystem.