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Chippewa Falls, Wisconsin

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How to Care for Goldfish and Koi in Ponds

Prior to adding fish to your pond, please ensure that:

  • Your water looks and smells reasonably clean -- not putrid. Some algae growth is normal and even healthy for the fish.

  • Be certain there is no chlorine, rotting plant/animal matter, or heavy sludge on the bottom.

  • Test your water if you are in doubt. pH should be around 7, nitrates under 40 ppm, nitrites 0, ammonia 0, carbonates (KH) 120-180. Most healthy ponds naturally fall within these parameters. Temperatures should not regularly exceed 80 degrees.

When you bring your fish home, float the bag or bucket 1/2 hour to acclimate the fish before release.


  • Provide cover and protection from predators in the form of plants and/or caves.

  • Feed fish once or twice a day, only as much as they can eat up in 3-5 minutes. Remove any leftovers. New fish are insecure and appreciate sinking food (buy special food or soak pellets ahead of time so they will sink).

  • Notice any unusual behavior -- if fish aren't acting normal, test your water. Chasing is breeding behavior and not cause for concern.

  • If the pond is new or heavily stocked, test water frequently. Also test anytime there is a change in water quality or clarity, especially if accompanied by unusual behavior in the fish.

Goldfish and Koi do exceptionally well in ponds. They have more room and better water quality than they ever get in aquariums. If your fish were healthy to start with and you follow these directions, they should continue to grow and flourish all season. They may even provide you with some babies!

Fall and Winter Care

Switch to a wheat germ based fish food when nighttime temps drop below 55 degrees. Fish will eat less. Once a day feeding is sufficient. Do not feed at all if water is below 50 degrees.

Fish can winter in the pond. Clean out any dead leaves. Use a heater to keep a hole open and a small pump in the bottom to keep water circulating. If your heater is more than 2 years old, we recommend getting a new one to have on hand in case it fails during the winter (2 years seems to be their typical life span).

If you bring your fish indoors, provide the largest tank you can, add salt at the rate of 1 tsp. per gallon, cover the tank with a screen, keep it in a cool place, feed sparingly (if the water is >50 degrees), and test regularly for ammonia and nitrite.

Return the fish to the pond in the spring after a thorough cleanout and after the water temperature stabilizes (May).


  Stop by our Pond Shoppe where you'll find everything you need to care for your fish!