During the fall season, it is important to prepare your pond and fish for the winter ahead. During the summer, even with the use of skimmer filters, it is possible for a fair amount of debris to accumulate on the bottom of the pond. It is important to try to remove as much of this material as possible before winter to avoid the development of organic waste products that can rob the water of its oxygen. You can use skimmer nets and pond vacuums to help remove this pond debris, or possibly go wading in the pond to physically remove the muck. While you are doing this you also perform an important water change to help remove any chemical wastes that have accumulated in the pond. It would not be unusual to change up to 50% of the water volume to freshen the water. It is best to do this maintenance before the water temperature drops below 60 – 65F. This will help you maintain optimal water conditions throughout the winter.
You can also add bacterial preparations to help digest the excess organic debris and decompose larger leave debris. It will also help establish colonies of the bacteria for the following spring, accelerating the re-conditioning of the pond after the dormant winter season.
Depending on the location of the pond, you may need to place pond netting over the surface of the pond to help prevent any leaves from falling or blowing into the pond. This light weight nylon mesh is simply staked around the edges of the pond and draped over the entire surface. Once the majority of the leaves have fallen from the trees, you can remove the net and use a skimmer net to collect any stray leaves that manage to blow into the pond. It is much easier to remove this type of debris while it is floating on the surface than after it sinks to the bottom of the pond!
As the temperature of the water starts to drop, you will want to switch the fish to a wheat germ based diet, high in carbohydrates, lower in protein. This food is more easily digested at the lower temperatures. Once the temperature is below 60F, you should feed them wheat germ based foods exclusively. After the temperature drops below 50F, stop feeding altogether, no matter how much the fish “beg” for food; they simply cannot digest any food they swallow. The high carbohydrate diet will help the fish develop the needed stores of energy to survive the dormant period before spring.
Before the first frost, you should remove any filtration units, drain and place them into storage. You can keep a water pump or air pump running, and depending on your location, keep it running all winter. If you are in an area with long periods of freezing weather, it will be better to use a pond de-icer to maintain a small open area to facilitate gas exchange, preventing a build up of excessive carbon dioxide levels. On larger ponds you can also float a log to help maintain an open space. You never want to physically break the ice as the vibrations can disturb the fish.
Following the above simple steps can help ensure that your fish remain healthy during the winter season and the pond is ready to come alive in the spring.