Koi ponds are revered in Asia as the perfect artistic environmental blend of showy plants and colorful fish. If built properly, a koi-stocked pond becomes a year-round ecosystem that is not only a pleasure to own but an actual property investment.
"Koi" or "nishikigoi" (Japanese for "brocaded carp") are a fish whose fossil lineage stretches 20 million years to southern China. Not to be confused with goldfish or common carp (although related) koi are often referred to as "living jewels" or "swimming flowers."
Popularized in Japan during the late 19th century, koi were farmed in rice paddies as high source of protein. Over the century, the prolific fish found their way to ornamental garden ponds in the West.
Today's koi come in 13 varieties. Each contains a number of sub groups and are classified by colors and patterns, ranging from bright orange and white (with black irregular spots) to solid silver or blue with reticulated net-like scales.
They are said to make great pets. They hear, taste, and smell, blush red when stressed. They can even be trained to take food from your hand. Koi have voracious appetites but should not be fed more than twice a day, with enough food to be totally consumed during one feeding.
You can kill koi by accidentally overfeeding. This happens because the fish excrete excessive amounts of ammonia, making it difficult for them to breathe. That weakens their immune systems to infection and parasitic invasions. Proper filtration and pump equipment can also lessen the chance of that happening.
Koi that spend the winter outside should cease being fed when temperatures dip below 50 degrees Fahrenheit. Their metabolisms slow down and they go into a semi-hibernation state.
Once milder days return consistently they may go back to their normal feeding schedule. It's also a good idea to provide a deep enough pond (at least three feet) so your koi have a place to rest on the bottom during frigid spells. Adding a pond heater and keeping formed ice aerated is also important for winter care.
Female koi begin to spawn at around three years of age, laying thousands of eggs. Hatchlings start life about one-sixteenth of an inch in size and should be culled to prevent overpopulation. Within ten years, if well cared for in a spacious pond, koi can easily reach three feet in length and tip the scales at around 25 to 30 pounds.
Their average life span is between 40 to 70 years but not uncommon for certain varieties to live 100 plus years and be handed down from one generation of human caretakers to the next. Unusual or fancy mature koi, when full grown, fetch thousands of dollars on the retail market, so it's an investment that enhances more than your property value.
Plants and flowers are also an integral part of your pond and provide an idyllic and healthful setting for your fish. Check with your local garden center to see if they stock pond exotics. Paradise Water Gardens in Whitman, Mass., at 800 955-0161 (www.paradisewatergardens.com), is one of the oldest water garden centers that ship fish and flowers nationwide.