Koi FAQ
Content
General Questions
What's the difference between Koi and goldfish?
Koi (Cyprinus carpio) and Goldfish (Carassius auratus) are both in the same family: Cyprinidae. All Koi have the same body type, but very greatly in color. They can also grow up to two to three feet in length. Most goldfish are are orange in color, with a few types that also have black, white and calico colors. They come in a wide variety of body shapes, but stay relatively small in size.
How long can Koi live?
Koi usually live around 20 or 30 years. The oldest Koi on record was named Hanako. It purportedly lived to be about 226 years old. It lived in a pond that was in a stable area (read low geologic activity) and was passed down from generation to generation. Hanako died around 1977.
What kind of food should they eat?
During the summer, when the water temperature is above 60 degrees Fahrenheit, feed your Koi fish a high protein Koi food. During the fall and spring, when the water temperature is between 52 and 60 degrees Fahrenheit, feed them an easy to digest wheat germ based Koi food. When the water is below 52 degrees, stop feeding your Koi.
How big do Koi get?
Most domestic Koi usually grow about 12 to 15 inches long. Japanese Koi usually grow 22 to 26 inches in long. Jumbo sized Koi grow up to 34 to 36 inches long.
Does the size of the pond hinder a Koi's growth?
The size of a pond will not stop a Koi from growing. The size of the pond, along with other factors like health, feeding, water temperature and water quality affect the speed of their growth. A Koi will keep growing until it has reached its genetically predetermined size.
Can Koi and goldfish live together in the same pond?
Yes, Koi can goldfish are both docile and can live together. They can live any species of fish that is considered "docile".
I have a filtered, thousand gallon pond, how many Koi can I put in it?
You can put about ten small Koi in it, but as they grow you will need to find new homes for a few.
How many gallons of pond water per Koi fish would you recommend?
We recommend the following GPK (gallons per Koi) rates based on their size:
Small Koi (2" - 8"): 100 - 150 gallons
Medium Koi(8" - 14"): 250 - 300 gallons
Large Koi(14" - 24"): 400 - 500 gallons
Jumbo Koi(24" - 36"): 750 - 900 gallons
The GPK estimates are based on long term housing for the Koi. Indoor winter tanks can be small, but must accommodate enough room for the Koi to swim around comfortably.
What is the temperature range that Koi can live in?
Koi can live in water that ranges in temperature from 34 degrees F to 90 degrees F. They won't thrive at the extreme temperatures though.
Can Koi stay in the pond during the wintertime?
They can stay in the pond as long as you keep a hole in the ice with a de-icer. It allows fresh oxygen to enter the water and carbon dioxide to escape. Other measures like adding a bubbler near the surface, a backup de-icer (in case the primary one fails) and an aquarium power head to move the water at the surface to keep a larger portion of the pond open will help get them through the winter. For more information, read our article on wintering Koi.
Will big Koi eat smaller Koi? Can I have mixed sizes in my pond?
Koi are omnivorous and they may eat Koi fry or eggs, but they will leave smaller fish alone.
How much do your Koi cost?
Our tosai (one year old Koi) cost $50. Medium, large and jumbo sized Koi are priced on a per fish basis depending on: size, body conformation, skin luster and color.
What's the difference between Domestic, Imported and Japanese Koi?
Domestic Koi are any Koi fish that are bred in the US. Imported Koi are brought into the US from another country that produces Koi. Japanese Koi come from Japan and only Japan. Unscrupulous dealers will call domestic Koi "Japanese" if they came from imported Japanese brood stock but were bred in the US. Some will also try to pass off "imported" Koi as being superior to domestic, even though they can come from any breeder in any country with no quality control.
Why are Japanese Koi so sought after?
Japan is where the hobby originated and where the standards were set. Many breeders have been in business for several generations. The bloodlines the Japanese breeders have cultivated exist nowhere else in the world. The bloodlines and breeding technique the Japanese use have created quality Koi fish that grow bigger and have better colors than any other breeders in the world. These are the reasons Japanese Koi are so sought after.
What makes for a really good Koi?
Koi are judged on body conformation (no physical defects), color and skin luster.
What was the most expensive Koi sold for?
Grand Champion Koi at the all Japan Koi Show usually sell for six figures. A few have even sold for seven.
Is it ok to buy Koi from eBay or Craigslist?
We recommend that you quarantine any Koi you buy to prevent a disease outbreak in your pond. Discuss testing and health with the person that you are buying from. We quarantine each shipment of Koi in our facility for about a month and we test our Koi for KHV, Spring Viremia and Asian tapeworm.
I'm going on vacation for a couple weeks. Should I have someone feed my Koi? How long can they go without me feeding them?
Koi can go a couple weeks without your feeding them during the summer time. They will eat bugs and will nibble on the algae on the sides of the pond. You should have someone check on your pond regularly to make sure it is operating correctly and the Koi are alright.
Will my Koi pick on a new one when it it introduced into the pond?
Not at all, Koi are docile and will accept a new addition to the pond with no problems.
Why are most of my Koi bumping and slamming one of the larger ones into the pond walls?
If its spring or early summer, your Koi are spawning. Spawning is triggered by rapid changes in water temperature.
How often and how much should I feed my Koi fish?
Feed your Koi fish as much food as they will eat in about a couple minutes. Do this a couple times a day.
My Koi tear apart and eat my pond plants. Is this normal?
Unfortunately, yes. Koi are omnivorous and love to eat pond plants, which they find delicious. Small Koi won't do much damage, but large Koi will uproot your favorite lily. We suggest cordoning off a section of your pond or even having a separate pond for plants altogether.
Koi Health
My Koi bumped itself on something in the pond. There is a spot about the size of a dime that looks red and inflamed. What is it and what do I do about it?
It may be an ulcer. Ulcers form when an injury or a parasite infestation damages the slime coat and scales, allowing bacteria to enter the wound. When an infection sets in, an ulcer forms. Treatment options for ulcers include antibacterial dips, medicated Koi food or with an antibiotic injections. Consult with a veterinarian on the method of treatment that will be most effective for your Koi.
My Koi jumped out of the pond and was out for a while before I found it. It is pretty dry, but is still moving around a little. Can I save it?
As long as the gills stay moist, you still have a good chance of bringing your Koi back. Set it in the pond in a net while you get a plastic tub and fill it with pond water. Add an airstone to heavily aerate the water and place the Koi in the plastic tub. Hold it upright until it comes around and is able to swim upright (being out of the water for long periods of time messes up their swim bladder). Keep an eye on the Koi for the next few days. You may want to give it some medicated Koi food to stop an skin infections that could pop up.
Are some Koi more susceptible to disease than others?
The newer, more exotic varieties ten to get sick more. They are bred to bring out their color and not to improve their immune system. Special care in needed to maintain a clean and healthy pond environment. Older varieties of Koi tend to have stronger immune systems since their bloodlines are established.
Ponding
My fish have outgrown my pond and need new homes. Will you take them?
We do not take any fish back once they leave our facility. We only bring in Koi from our trusted Japanese breeders. We maintain strict quality control and health measures, bringing a fish into our facility from an unknown source will compromise those protocols.
I have a pair of ducks that come to my pond every spring. It is ok for them to be in the pond with the Koi?
Wild ducks might eat small Koi and they could introduce aquatic parasites. They will also foul up the water with their waste, so they should be kept out of the pond. Domestic ducks can go in the pond if it has adequate filtration to handle the waste load.
How often do I have to clean the pond?
If your filter system keeps the pond clean and no leaves or other debris are in it, then won't have to clean it out. If your pond is poorly filtered and waste accumulates on the bottom, it should be cleaned every couple weeks.
Is it alright if my dog swims in the pond?
It's ok for a dog to swim in the pond as long as it doesn't disturb the Koi, puncture the liner with its claws or have any pesticide treatments (for fleas, ticks or lice) applied on its skin.
Can I have rock in my pond?
You can have boulders along the sides, but the bottom should be left open so the bottom drain can do its job.
A heron is coming to the pond and trying to take my fish. What should I do?
Cover the pond with a net. It will prevent the heron from getting the fish. Eventually the heron will figure out that it can't get food from your pond. If your one of the lucky people that live along a migration path, you may want to consider altering the pond and landscaping to prevent herons from getting near it.
How deep should I make my pond?
Your pond should be at least four feet deep in Minnesota. We need the depth here in case your deicer fails and your pond freezes over. Having a deep pond a If you live in a moderate climate , your pond can be around three feet deep. If you live in a hot climate, your pond should be at least four feet deep to help prevent it from overheating.
Do I need a fence around my yard or around the pond?
You will need to check your local ordinances. Most towns have a maximum depth a water feature can be before you need to erect fencing around your yard.
Where is a good spot in my yard for a pond?
We suggest that you install a pond near your house, by a patio or and area of the yard where people congregate, which make viewing the Koi easy.
I get a lot of leaves in the pond. How can I stop this?
Covering the pond with a net will prevent leaves from getting in the water. Take the leaves off the net often so they won't accumulate and drop it into the pond. If you rebuild your pond, design it with bermed or raised edges to keep leaves from blowing in.
Why is my pond water green colored? I can't see my fish.
Green water is caused by free floating algae. Algae lives off of the waste that fish produce. Adding a UV sterilizer to the pond will clear up the pond water.
Why is my pond water brown in the spring or after it rains?
Brown pond water is caused by tannins that leach into the water from leaves and wood chips. Landscape around the pond to prevent rain water from flowing through the wood chips and into pond. Also, keep leaves out of the water in the fall.
How do I get rid of string algae?
Adding a protein skimmer will hinder the growth of string algae. A protein skimmer will remove the microscopic particles of waste that are too small for a mechanical filter to handle. Fish waste is a nutrient source for algae, removing all of it will keep it from growing.
Will covering the bottom of the pond with small rock extend the life of the liner?
45 Mil EPDM rubber liner has a 20+ year life span. Covering the liner with rock will prevent some UV deterioration, but will entail extra work year after year when you'll need to clean it out (you have to do it by hand, tools can puncture the liner).
It's springtime. When can I start up my pump/pond?
You can start the pond up when the temperatures stay above freezing for a couple weeks. The best time to start up the pump is when the air temperature stays between 50 and 60 degrees F during the day. If you have a pond problem, you do not want to get wet when it is very cold outside.