No they should be ok. You should run the pump all year round. It'sunlikely to
freeze with water flowing through it and it will keep theammonia and nitrite
down although the bacteria is not as active.

In weather that cold you need to shut down the pump for the winter. Water temp
is warmer on the bottom, and it will take away that warm bottom layer You say
zone 8, but you must be colder if you freeze......if you ARE in zone 8 raise
the pump to a few inches off the bottom ....which is where all pumps should be
for safety reasons anyway.
.You needsome oxygenating plants.
water lilies are popular but get ones that aresuitable for your pond size and
depth.
Water hyacinth and lettuce aregood to give the fish shelter from the sun,
they won't survive thewinter but the others will and should be left in. If you
add some
potash it will help the plants to take up the nitrate and that willkeep the
algae down.- Any recomendations as to what type of plants to put in the pond?
We live
in central oregon (zone 8, I believe).

I don't know what your budget is, but this is bare minimum, and you can go from
there. If I could only buy 2 plants it would be a water lily ( hardy) and
several bunches of anacharis ( oxygenator) I think it is a little late for
buying water hyacinths since they die every year....but they are the first
things to put into the pond in the spring. For a pond your size I would get
one med to large lily. My 2 favorites are Colorado ( a soft salmon color
with green leaves) it is one of the very most generous bloomers of all the
lilies and an arc en ciel. It starts out very pale pink and is white by
the 3rd day. The leaves on it are marbled and are green, pink, red, and white.
I have areas in my ponds that are several feet square with anacharis....it
is food, hiding area and oxygenator all in one little plant. The water lily
leaves will probably die back in winter ( unless you are in zone 8...then they
just get sparse) but in summer they will shade almost the whole pond, and give
wonderful blooms as well. I have had as many as 11 blooms on Colorado and 5 on
arc en ciel at one time...add to that 36 hyacinth blooms.....a really
pretty goldfish pond. ( I really need to get in it and thin them out, but
just got out of the hospital so it will be a while.....I hope this helps good
luck to you Jerri

http://www.fringeweb.com/Ponds/JerrisPond