Koi Pond Winter Care Tips
Koi and other hardy pond fish require special care during the fall months. If you live in a region that experiences extended periods of freezing temperatures, pay particular attention to water quality during fall to help ensure over-wintering success.
The question is often asked…. How do my pond fish survive without eating much during the cold parts of the year or even under the ice? How can I help them?
Koi and goldfish are poikilothermic (cold-blooded) and thus their metabolism is determined by the temperatures of their surroundings. As the temperatures drop, koi and goldfish slow down and their nutrient requirements are greatly reduced. A lot of the needed energy is derived from fat reserves built up during the warmer waters temperatures. Pond fish DO eat during the cold weather periods; however, it is very infrequent and can stop when temperatures drop into the 40’s. As the temperatures drop below 60 degrees, koi and goldfish can benefit from an easier-to-digest diet containing a higher level of plant materials such as wheat germ.
As the water warms up in the spring, your pond fish will become more active and look for food. They will tell you when they are ready, as they will roam the pond sampling tidbits of pond edges and greet you for a feeding.
Preparation for cold weather is the key. Many steps will ensure your wet pets get the best conditions possible.
- Proper feeding keeps them in shape.
- Cleaning pond bottoms and filters will reduce ammonia build up over winter.
- Addition of sludge eating/fall winter bacteria will help ensure the best fauna in the bio-environment.
- Checking and repair of pumps etc prior to the cold ensures a hassle free cold season.
- Ensure proper aeration and degassing by keeping holes open in the ice using a de-icer when the pond surface freezes.
- The best-case scenario would be to bring your pond fish into an aquarium or indoor pond of adequate size so you can enjoy them throughout the cold season.
The best thing about koi and goldfish is the fact that they are easy to care for and very hardy. They have the ability to thrive in a variety of environments.
There are some things we will be doing different next year to improve our present design.
- Because of the width of the pond, we had to use two pieces of the green house plastic to get a complete cover. I intended on splicing the two pieces but as we began to complete the cover, I was worried about the splice failing with the weight of a large snowfall. Instead, I ran the second section of plastic under the first covering about 6 feet of one side of the dome.
The pond was covered in October and condensation inside the dome was heavy without any freezing weather. What we didn’t realize was the condensation was running down the inside of the first sheet of plastic and pooling on top of the second piece near the edge of the pond. Before I could do anything about it, a 4-foot section of the dome collapsed and rested on the surface of the pond. The next couple of days were bitterly cold and the pooled condensation froze. Hoping it would be ok, we left it and just kept a close eye on it. The weight of the ice from the condensation and a couple heavy snowfalls made this section of the dome collapse even more causing me to enter the dome and cut away the section that had collapsed in order for the pvc ribs to regain their original placement and keep the rest of the structure from failing.
- Placement of the aerator was also an issue this year. I had placed the aerator inside the dome about 2 feet away from the edge of the dome walls. As snowfall after snowfall came and went, the amount of snow that piled against the walls of the dome eventually pushed in enough to cover the aerator causing it to burn out.
- Structurally, the support ribs had been placed every four feet.
The sand bags worked great and we will use this method again next year for securing the cover. The cover will be removed this weekend to open the pond for spring, details to follow!
In smaller or shallow ponds where the water freezes solid, all plants will need to be brought indoors and stored for the winter. You are able to pack these plants in dampened peat moss and then they can be placed into the bottom of a refrigerator or root cellar for winter storage.
Non-hardy plants will need to be brought indoors for storage and some tropical plants may be able to be kept over the winter indoors as houseplants. When storing non-hardy plants, you will need to trim all of the plant to about 2” above the soil. You can then place the plant in a bucket, cover it with damp peat moss and store it in a cool dark area such as a refrigerator or root cellar for the winter. Make sure to hydrate the peat moss several times during the winter.
Tropical Water Lilies and floating plants will not survive the winter in the pond if the surface of the water freezes. These types of plants will need to be housed indoors during the winter. An aquarium with plant lighting and a heater set to about 70ºF is recommended for wintering these plants in your home. Plants should not be fertilized during winter storage, as the plants will need this time to remain dormant.
Croatian Center of Renewable Energy Sources (CCRES)