Although you can choose to bring fish indoors in cold climate locations, many Aquascape ecosystem ponds are built with the intention to overwinter koi and goldfish while accounting for fish health. To ensure the system is set up for overwintering koi and goldfish here are a few things to consider.
Depth of the Pond
- For overwintering outdoors, the pond should be at least 2 feet deep in colder climates. This depth allows the water at the bottom to stay above freezing, providing a more stable environment for the fish.
Aeration and Oxygen Levels
- Adding a pond aerator or maintaining a small water pump will ensure that oxygen levels stay high, which is essential for the fish in colder months when ice can restrict gas exchange.
- The aerator should be positioned at a shallower depth so that it doesn’t disturb the warmer water at the bottom of the pond, where the fish will naturally migrate in cold weather.
De-Icing
- A de-icer, or pond heater, can help keep a small section of the pond ice-free, allowing toxic gases to escape and oxygen to enter. Keeping this hole open is crucial for fish health, as sealed ice can lead to a buildup of harmful gases.
Water Quality Maintenance
- Remove any excess debris (like leaves and sludge) from the pond to keep water quality high. As temperatures drop, biological activity slows, meaning fish produce less waste, but buildup from the fall can still degrade water quality.
- Consider adding cold water beneficial bacteria treatments before the water cools to further reduce organic matter in the pond.
Diet and Feeding Adjustments
- As water temperatures drop below 50°F (10°C), fish metabolisms slow down, and they no longer need to be fed. Stop feeding once temperatures are consistently low to prevent uneaten food from decomposing and affecting water quality.
Indoor Considerations
- If you decide to bring your fish indoors, set up a large enough holding tank or indoor pond to accommodate them comfortably.
- Ensure the indoor setup has proper filtration, aeration, and stable water temperatures. A heater may be necessary to maintain a suitable environment, depending on the room temperature.
- Gradually acclimate your fish to the new water temperature when transitioning them indoors to prevent shock.
Monitoring Fish Health
- Regularly check your fish and the pond for signs of stress or poor water quality, especially during the seasonal transition. Cold water diseases can affect fish, so monitoring is crucial.
By considering these aspects, you can successfully overwinter your koi and goldfish outdoors or make an easy transition to an indoor setup if necessary.