Common Koi Pond Frequently Asked Questions
1. What distinguishes Koi from goldfish?
Goldfish (Carassius auratus) and Koi (Cyprinus carpio) are members of the same family, Cyprinidae. Koi generally have very homogeneous body types, but individual fish display a wide color range. They can grow surprisingly large; mature koi can reach lengths of two to three feet. Goldfish, on the other hand, have less varied colors. The majority of them are orange, with a few fish showing black, calico, or white coloration. Goldfish have diverse body shapes, but they remain small even when fully grown.
2. Is it possible to keep goldfish and Koi in the same pond?
Koi and goldfish are both very docile species, and they can definitely live together. In fact, Koi are suitable for living in close quarters with any docile species of fish. Often times our customers also have feeder fish to help reduce the mosquito population as they feed specifically on bugs. This also works as a great alternative if you dont want koi or goldfish, but you do want a water feature without mosquitoes.
3. How large can Koi get?
As noted above, the largest Koi can reach three feet in length. These are known as Jumbo Koi. Japanese Koi reach a length of 22 to 26 inches. Domestic Koi typically mature at a length of 12 to 15 inches.
4. Is a Koi’s size constrained by the size of its pond?
Koi can grow very large even in cramped quarters. Pond size — along with factors such as water temperature, diet, and health — will impact the rate at which Koi grow. Koi will grow until they reach their hereditary size.
5. How much water does a Koi need in its pond?
Based on the size of the individual Koi, we recommend the following allowances of water:
- Small Koi – 2 to 8 inches – 100-150 gallons
- Medium Koi – 8 to 14 inches – 250-300 gallons
- Large Koi – 14 to 24 inches – 400-500 gallons
- Jumbo Koi – 24 to 36 inches – 750-900 gallons
6. How deep does my Koi pond need to be?
Here in Minnesota, you need to make your pond at least four feet deep. In this region, depth is vital in the winter. If your pond’s deicer fails, a little extra depth will preserve liquid water beneath any ice that forms on the surface. Four feet is also a good depth for Koi ponds in hot climates. The depths will serve as a reservoir of cooler water, moderating the overall temperature of the pond and preventing overheating. In moderate climates, we suggest building your Koi pond to be roughly three feet deep.
7. What temperature range is suitable for Koi?
Koi can survive anywhere between 34 to 90 degrees Fahrenheit. Be aware that the fish will hardly be thriving at the extremes of this temperature range, though. Most of our customers are located in Southern California, including Orange County, Los Angeles, Riverside, and San Diego in which these ponds don’t need heaters, but should have at least 36″ of water with a place for the fish and turtles to get away from the sun on hot days if needed.
8. What do Koi eat?
In warm summertime waters (over 60 degrees Fahrenheit), your Koi fish need high protein food. In the spring and fall, when the water is between 52 and 60 degrees, Koi need a Koi food that contains easy-to-digest wheat germ. You do not need to feed your Koi when the water temperature is below 52 degrees.
9. How often should I feed my Koi? How much food do they need?
Feed your Koi for a few minutes at a time. Give them as much as they are interested in eating. Repeat this process once or twice a day.
10. I’m going to be out of town for a few weeks. Do I need to get a friend to feed my Koi? How long can they last between feedings?
Koi will be fine with a two-week break in between feedings during the summer months. They can scavenge some nutrition from their environment by nibbling on algae and eating insects. It’s a good idea to ask someone to check your pond regularly to ensure the Koi are healthy and everything’s operating normally.
11. How often does a Koi pond need to be cleaned?
Koi pond maintenance can be very simple. As long as your filter system keeps the water clean and there isn’t any surface detritus (such as leaves), your pond doesn’t need cleaning. If you don’t have good filtration and you can see waste accumulating in the depths of the pond, clean it out every two weeks. We also suggest adding the appropriate pond equipment to your water feature to help handle the amount of koi and turtles you might have.
12. My Koi pond seems to be a magnet for leaves. What can I do about this?
Putting a net over your pond will keep leaves out. Check the net regularly and keep it clear of leaves so that they don’t wind up dropping into the pond. Consider remodeling your pond and building up raised edges around it. These will act as windbreaks and cut down on the number of leaves that blow in. Take the time to eliminate pond weeds if you find them shedding into your water.
13. What should I do about string algae?
String algae can be controlled by installing a protein skimmer in your pond. Algae feed on the waste your fish leave behind, so eliminating all waste will cut down on string algae. Protein skimmers eliminate microscopic waste particles that get left behind by a mechanical filter. If your pond is large and you need recurring algae and weed management services, contact us for a free quote.
14. Can I extend the life of my pond liner by covering the bottom with small rocks?
A proper pond liner (45 mil EPDM rubber) should last 20 years or more. While a layer of rock will prevent deterioration due to UV light, it will also require a lot of extra pond maintenance to keep the rocks clean. (This cleaning has to be done by hand to avoid tearing your liner.)
15. Spring is here! What’s the right time to start up the pump on my pond?
Wait for the temperature to stay above freezing for a week or two before starting your pond up. Ideally, you want air temperatures that stay between 50 and 60 degrees Fahrenheit when you activate the pump.
16. My pond gets visited by ducks in the spring. Is this OK for Koi living in the same pond?
Wild ducks pose some minor risks. They may spread aquatic parasites and even eat smaller Koi. They also leave behind waste, fouling your pond. It’s best to keep wild ducks out of your Koi pond. Domestic ducks are generally safer, provided your pond’s filtration system is capable of handling their waste.
17. My Koi are attracting unwanted attention from a heron. Help!