Koi add color and movement to your pond. They're relaxing to watch. And they're likely the centerpiece of your water feature. But how much do you really know about your finned friends? Check out these five factoids about koi and impress your fish-keeping pals during your next pond-side shindig.
- Life Expectancy of a Koi Fish: Have you heard of Hanako? He's the fabled koi who lived for 226 years after being supposedly passed down through the generations and was aged by counting rings on his scales. Hanako has been proven to be an urban myth to set the record straight. The typical lifespan of a koi fish is 25 to 35 years in a well-maintained fish pond - but that's still not a bad life span, all things considered!
- Growth Spurts: Koi, like most other fish, start out as teeny-tiny fingerlings and grow to their genetically determined adult size. But unlike many fish, koi will grow to fit their accommodations - which means they'll develop into super-sized beasts in the right environment. In their first three to four years of life when housed in an adequately sized pond, a koi will reach about 18 inches long. Throughout its lifetime, it can grow to reach up to 3 feet and more. That's some big fish!
- Colorful Gastronomes: The ultimate underwater foodies, koi will eat just about anything, with the exception of meat. Though they love their pelleted diet, like The Pond Guy Growth & Vibrance Fish Food, koi will happily gobble down lettuce, apples, oranges, watermelon, and even tiny shrimp. So why not treat your scaly pals to some nutritious fruits and veggies now and then!
- Feast and Famine: Koi love to eat and will chow whenever food is offered, but these guys can actually go more than 10 days without food during the warmer months - and fast even longer when temperatures drop and they go into their winter torpor, or hibernation, when they pass on meals for months at a time. Of course, if you feed your fish regularly, don't suddenly stop as doing so can affect their happiness and overall wellness.
- Koi Agility? No, koi unfortunately cannot be trained to jump through hoops like a dolphin or fetch a floating ball like a Labrador, but they can be conditioned to recognize your footsteps and come to the water's edge for a visit. Simply feed your fish from the same place consistently and, before long, they'll learn to go there for food and even learn to eat from your hand! Now that's a cool party trick.
- Do They Drink Water? You would think that your koi need a drink of water like the desert needs another grain of sand but just like us; they too need a little refreshment from time to time. Koi utilize water to maintain proper body functions the same as us but they just do it a little bit differently. Koi don't per se "drink" like we do. Koi absorb water through their gills and body in a process called osmosis.
Osmosis is defined by dictionary.com as "the tendency of a fluid, usually water, to pass through a semipermeable membrane into a solution where the solvent concentration is higher, thus equalizing the concentrations of materials on either side of the membrane." In other words, koi have larger concentrations of water that contain salt in their body than does the surrounding water garden. Through osmosis water is constantly passing through koi's semipermeable skin into their body to equalize these concentrations. Since water is constantly absorbing into their bodies they have to immediately excrete this water to prevent them from bursting. During the course of a day, they can excrete up to 10 times their weight.
Last Updated: October 23, 2023