"Janet" wrote in message
...
You're 100 % correct MC, koi are not goldfish and vice versa. Koi absolutely
do not do well in water under about 40 degrees. They may make it but it can be
a real struggle in the spring as in their weakened state they are very
suseptable to parasites and bacterial infections...
Janet in cloudy Niagara Falls


http://www.aquariumpharm.com/article...-wintering.asp
The metabolism of koi and goldfish is controlled primarily by water temperature.
As the water cools, pond fish require less protein in their diet. When koi and
goldfish are fed high-protein food in cool water, the excess protein is excreted
as ammonia from the gills. The microscopic organisms that make up the biological
filter (and consume ammonia) also slow down in cooler water. Improper seasonal
feeding can lead to a build-up of toxic ammonia, which stresses fish and reduces
their winter survivability. When the water temperature drops to approximately
65° F, start feeding with Spring & Autumn Pond Food. This type of fish food is
better suited for the dietary requirements of pond fish in cool water and won't
pollute the water with excess ammonia. Some water gardeners continue to feed
their fish until they no longer come to the surface. I stop feeding my pond fish
when the water falls below 42° F.

There is no need to worry about "frozen fish" if a section of the pond is at
least 18 inches deep. Pond fish will seek the deepest part of the pond and
over-winter there until the water warms in the spring. If your pond is less than
18 inches deep, the fish may freeze during a harsh winter. Check with your local
pond supplier if you live in an area with harsh winters. Water gardeners with
shallow ponds can keep their koi and goldfish in kiddie pools or aquariums set
up in a cool basement or garage. All that is required is an aquarium air pump or
small fountain to provide oxygenation. The fish are fed infrequently, if at all,
depending on the water temperature. pH, ammonia and nitrite should be monitored
weekly, especially if the fish are fed. Small water changes (20%) each month
will keep the water in good shape until spring. Koi are "jumpers"-so be sure to
cover the pool with bird netting!

http://www.wetwebmedia.com/PondSubWe...dmaintwint.htm

Fishes: Koi, goldfish, natives and other cold-water fishes may over-winter in
your system; providing that some of the surface

area does not freeze over completely. If your fishes are fat and healthy in the
fall, their metabolisms will be depressed enough accordingly to prevent
mortality. The rule with dealing with livestock especially during the winter is
the less disturbed the better. Instances of high mortalities are almost always
attributable to poor design, overcrowding or inadequate cleaning before the cold
season; or handling them after.

Livestock should not be fed below a temperature of 50 degrees F.; The fish may
seem interested and eat, but be unableto use the food and consequently the water
will be fouled. Partial water changes should be of small volume, if any,
infrequent and literally dripped refilled. Prior to cold water hibernation your
fish(es) should have been well fed, checked for disease and disinfected if
necessary.

Here is a link to some folks who overwinter their koi in Ontario:

http://backyardpuddle.aaquaria.com/season.html


"MC" wrote in message
om...
Again, if the combination of your climate and depth of your pond
allows, a deicer is great, but I don't think it fits all situations.
Contrary to what many people think, Koi don't hibernate.

"George" wrote in message
...
"Janet" wrote in message
...


--

"MC" wrote in message
om...
After much research, I've decided to use solar bubble wrap pool cover
floated on the top of my pond and a titanium tube-style heater. The
pool cover will have a border of about an inch to allow gases to
escape. My questions a

1) How do you use one of these acquarium-type heaters? I would imagine
it would burn the pond liner if I just throw it in there. If I suspend
it, I would be concerned of it getting knocked loose. Do I need a
wire/mesh case to keep the fish from burning themselves?

2) I've read bio filters are useless below 50 degree. So I won't run
it. Is it better to remove it from the pond, or just leave it? I
anticipate the heater will keep my pond around 40. I don't intend on
"heating" it, just keeping it from freezing solid.



FYI: I am in zone 5, 500 gallons, 30" deep, 6 Koi

I'll agree with George here. We have a pool and last winter we left the
solar
blanket underneath the black winter tarp. It's didn't lessen the ice at
all.
The solar blanket just froze intot he ice. I'm in zone 6b and I use a
stock
tank de-icer in the pond. I don't think the aquarium heater is going to do
it...
Janet in Niagara Falls

The de-icer worked great for me.