Question for my In-laws

They have a small pond in SE NC USA and it is built into a small hill that
they fabricated w/ dirt/sand mix and rocks on the outside of the hill. They
usually have the pump that sprays straight upward running but w/ the cold in
the AM the top of the pond freezes and the pump does not look like it is
working. They do have a special grass in it for the fish (around 20 small
ones) and they have turned off the pump for the winter. However, they are
still trying to feed them. I did not think that they were to feed them
during the winter??? Should they try to keep the top of the pond from
freezing?? IE Braking the ice in the AM everyday?? Any suggestions?? I am
not an aquariist (is there such a word??) So I am asking for any suggestions
that they should know about for now and the future.
TIA!!
cjack

Feeding the Fish. The short answer to this is: Forget It, even if the
fish look interested. In colder water, fishes' digestive systems are
sluggish. The best option for the hobbyist is to feed easily digested
foods, especially those made from wheat germ, when the pond temperature
drops below 55o F.. Feeding should be stopped altogether when the pond
temperature drops below 45o F.. Wheat germ foods should be again
utilized in the Spring, when the water temperature is between 45o F.
and 55o F., to provide an easily digested diet after the long cold
winter.

Fish may be wintered indoors or outdoors, depending on the construction
of the pond and the inclination of the hobbyist. They can also be
"traded in" to us for credit (either immediate or for next year's
stock), but the law of supply and demand usually dictates very low
prices paid on pond fish during the off-season

Heater / De-Icer. We now stock several reasonably priced de-icers that
are safe for use in concrete, liner or even preformed ponds. The
classic version is powerful (typically 1250 watts or more) enough to
keep a small pond ice-free, or to allow a "breather hole" in a larger
pond, and have been tested at down to -10 o F.. They are preset to
operate only when the water temperature approaches freezing to save
electricity. Aquarium heaters are totally unsuitable for outdoor use;
should they break due to harsh weather, live electrical wires are left
lying in wet snow. In recent years, more energy efficient models of
de-icers have appeared on the market. Please see Pond De-Icers for more
details and our comparison guide.

Aerator. A large airstone operated by a standard aquarium air pump can
also keep a small opening in the ice, at least during milder weather.
Unfortunately, the precise placement of the aerator is hard to arrange
and quite critical to its success: if it's placed too near the surface,
it will simply freeze in place during colder weather; if it's placed
too deep, it could actually chill the pond by bringing slightly warmer
up from the bottom of the pond, and replacing it with the coldest water
from the surface. The aerator should ideally be placed about halfway up
from the deepest part of the pond and monitored frequently.

Water Pump. A water pump can also be used to provide an opening in the
ice, but with the same limitations as an air pump. A submersible pump
should be firmly mounted over the deepest part of the pond, far enough
from the surface that it doesn't freeze solid, and far enough from the
bottom that it doesn't circulate the lower layers of water. It also
needs to be near enough to the surface to circulate the upper layers
but not to allow pieces of ice into the intake. No filters other than
possibly a coarse intake prefilter should be used (imagine cleaning a
filter outdoors in February!), since any reduction in the flow rate
will increase the likelihood of the pump freezing in place. Also, no
fountain heads or waterfalls should be used; they create some
attractive ice sculptures, but actually drain the pond in the process.
Pumps should be inspected regularly; if they run dry or freeze solid,
they will likely be destroyed.
Covering the pond. Covering the pond, or even a portion of it, can help
protect it from extreme weather and drastically reduce the amount of
electricity needed if a de-icer (heater) is used, but the cover must be
raised above the surface of the pond to allow for gas exchange and an
insulating layer of air. Ideally, a wooden frame would be built over
the surface of the pond and covered with plywood, then insulating
materials like Styrofoam, straw or even mulch. This could then be
covered with a tarp or plastic sheet, to again trap in an insulating
layer of air. They cover must of course be sturdy enough to withstand
snow accumulation.

If wintering fish outdoors is impossible or unappealing, they may be
moved indoors. This should ideally be done before the pond temperature
reaches 55o F., to minimize any shock from adjusting to indoor
temperatures. Fish may be kept in large aquariums, small wading pools,
troughs or almost any other large non-toxic (galvanized metal is not
suitable) container that will hold water. The container should be as
large as possible, and have high enough sides or be fitted with a cover
to keep fish from jumping out. It should be filtered and aerated
(sometimes the pond filter will fit). Many hobbyists fill the indoor
holding tanks with water right from the pond to ease the acclimation
process and possibly shorten the "break-in cycle". Fish should be fed
regularly, but sparingly, since they are no doubt now in much more
crowded quarters. A diet including Spirulina will help keep the fishes'
colors from fading due to lack of sunlight.
The "Empty" Pond. After removing the fish, the outdoor pond should be
left nearly full, to counteract pressures from freezing and thawing
ground. A few plastic milk jugs, inner tubes or other containers
floated in the pond can be added to absorb some of the shock of the
pond water freezing and thawing. Drain or remove any plumbing or tubing
from the pond.

Hope those bits and pieces help you out

All this information comes from Aquatic Unlimited - but there are many
sites on the internet that will help you with the types of fish you are
wintering and how they will do.

We have approximately 50 Koi and Goldfish and have we have ceased
feeding them now for the Winter season.

Any pond or aquarium dealer in your area should be able to help you
out.

Good Luck and Merry Christmas