100-gallon containers make excellent indoor ponds for overwintering hardy goldfish. This size can easily contain 50 to 75 – 3˝ Calico Shubunkin goldfish if kept at 50°F. Aeration is provided along with large sponge filters. In this situation, the containers are not covered because the fish are small and will not normally jump. If larger fish were kept in this situation then the container should be covered with a jump-proof type of cover.
by Jamie Beyer
Midwest Waterscapes
J
ust how cold can it get in some parts of the Continental United States? Does it get cold enough to freeze ponds solid? It can get very cold, as low as -30 to -35°F. And yes, it can get cold enough to freeze some ponds solid. Small ponds and above-ground ponds are especially at risk of this happening. Larger, in-ground outdoor ponds of, say, 1000 gallons that are at least 2.5 feet deep can successfully overwinter hardy fish January/February 2013
without supplemental heat during these severe conditions. Please refer to my Sept/Oct 2009 Pond Trade article ( h t t p : / / w w w. p o n d t r a d e m a g . c o m / a r t i c l e s / a r - 7 3 / ) , “Overwintering Koi Under Thick Ice.” The outdoor techniques outlined in that article have worked for overwintering both koi and hardy goldfish in my own ponds as well as those of my clients for over 20 years. There are people with large in-ground ponds who successfully overwinter all their fish in certain winters, while in other winters they lose some or all of their fish. How can this be? This is due to all the variables that each pond experiences going into and during the winter, giving each pond its own uniqueness. The severity of the particular winter, the amount of organic matter in the pond, the number of fish and/or increase in size of fish over the years and the health of the fish going into winter are the proven variables. Some other variables are more theory than fact. Stay tuned for a future article on this subject. This article is for those people who have lost fish attempting to overwinter them outside which may be due to the above variables. It also is for people who have those small ponds in areas where the temperatures can get to 10°F. or colder. For all of these ponders there are three other options for overwintering fish. They are: adding supplemental heat, building a greenhouse-like structure over the pond, or moving the fish indoors. Supplying supplemental heat to an outdoor pond with a stock tank heater can be very successful, but it is imperative that aeration is also used. For mild winters the heat addition alone may be enough to overwinter the fish, but in more severe winters both heat and aeration are necessary. Always use aeration with the heater – it is too risky not to. Aeration that is too heavy in small ponds can create a current that the fish will have to fight all winter. They simply do not have that much energy during the winter and can die. In these situations, all that is needed is a good stream of bubbles located in the center and on the bottom of the pond. POND Trade Magazine
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