- 1). Add a vitamin and mineral supplement at the beginning of fall to encourage fish immune system growth and storage of fat. This enables them to survive their hibernation cycle. Only feed when fish are actively swimming if temperatures drop below 55 degrees F and only as much as they can eat in 10 minutes. Remove all remaining food. Do not feed when water temperatures drop below 45 degrees F.
- 2). Install a bottom-based aeration system to combat ammonia buildup by keeping a hole in the ice. Ammonia, a toxic byproduct of decaying plant and animal matter, fish waste and even gill function, is often the reason fish perish in the winter. As water comes in contact with the atmosphere it absorbs oxygen and creates a more habitable environment on the bottom of the pond where fish will congregate.
- 3). Remove tropical plants when temperatures drop below 60 degrees F. Plant them in pots and use them as house plants until the end of the cold season. Consider aquatic favorites such as water hyacinth and water lettuce as annual plants since they don't usually live through the cold months. Replace them each spring. Cut back hardy plants with pruning shears to 1 inch above their root stems and sink them to the deepest part of your pond where warmer water subsides.
- 4). Run your in-line biological filter until temperatures drop to the point where you risk freezing the outflow and diverting water from your pond. Once temperatures reach freezing, shut down your filter and let the water out via your drain plug. Remove any organic material from the filter. Remove submersible pond filters for the winter.
- 5). Remove as much organic material from your pond as possible. Use a dip net to take out dead plant material, leaves, waste and sludge, taking care not to stir up bottom sediment.
- 6). Check on your pond frequently during the coldest months to ensure your fish are in good health. If the pond completely freezes over with your aeration system operating, do not break the ice with a hammer or pick axe. Install a 115-volt electric pond deicer until a hole melts in the ice. If a deicer is not available, poor hot water on the surface until a hole appears.
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