winter for goldfish

Question
Hello

I have 4 small goldfish & 3 fancy goldfish.  They are outside in 150 gallon pond.  I have the the waterfall always running.  Is there any other type of air pump or something that I need for oxygen in the water.  I have plenty of oxygenating plants at the bottom of pond, i also have a water lilly and water iris.  My water is crystal clear my chemicals are always good.  I have a bio-filter that is connected to the waterfall but it is constantly running.  My fish stay at the bottom when it is on, when I feed them I turn it off and I leave it off for about an hour and it seems like they are happier when it is off they will stay up toward the surface.  I am thinking maybe they a little peace.  main question - I live in Alabama and the weather is crazy the weather is so dramatic it can go from 30's at night and then the next day it will go up to the 70's.  I watch the tempature of the water because I was told to quit feeding after the water hits 40.  the coldest that the water has gotten is in the 50's .  I know that the water temp does not change as quickly as the air but it still seems like it does get cold and then the next day the sun beems down and the water gets warmer.  I am not sure how to do this.  what do I do when the water hits 40 but then the days are still in 60's or 70's do I feed or not???     do I quit feeding the first time that I see 40 or do i need to keep watching.

I am very inexperienced with fish - only about 2 months now.  any advice will be wonderful.

thank you  

Answer
Yes, you can buy an air pump to oxygenate the water and help keep it open during the winter.  I use a Luft pump in my 153 gallon pond.  For more on overwintering, see http://www.fishpondinfo.com/winter.htm
How strong is your waterfall?  If it keeps the fish away, it may be too strong for your pond.  Your pond will fluctuate in temperature with the changing air temperatures but as you said, not as quickly.  Larger ponds change more slowly.  I feed my fish if the water is above about 50 degrees F.  If it's a warm day and it's going to be warm the next day, I'll give them some food.  If it's hot one day but it's supposed to go really cold the next day, don't feed them.  It's not an exact science.  I don't follow a set rule.  I don't check my daily pond temperature.  It's more something that I feel.  The fish usually won't come up to the surface when I walk by if it's too cold to eat (but not always).  If the water is 40 degrees F, that's too cold to feed even if it's a warm day.  I hope that helps!

Robyn
fishpondinfo.com