Question
Thanks. The pump is set on a rock and pulls water from around the middle of the pond depth.  The pump outflow flows a rather forcful but not fountain like plume of water to the surface.  I also have a 3' tube attached from the pump that pushes water onto the bottom of the pond.  I have made sure to keep that tube and its outflow on the bottom since the late fall.  Any issues with too much aeration and or temp mixing here?   -------------------------------------------
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-----Question-----
We have a pond that is approx 4x5 and kidney shaped about 22 24 inches deep.  We have 12 goldfish all about 4-6 inches long.  I took out the floating plants as they were getting discolored looking but the bottom plants are thriving (anacharis?) No food for a month or so.  I have a pump in the pond still going.  It has a nice outflow right above it keeping the water moving.  I understand there are pluses and minus to keeping it in. What do you think in my case? What happens when the snow completely covers the pond as I am sure this will happen here in NE part of MD.
-----Answer-----
I'm in Central MD and leave my waterfall going all year in my 1800 gallon pond.  In my 1800 gallon pond, I use an air stone and de-icer.  Your pump is outflowing just beneath the surface and not out of the pond, right?  If so, then there should be no problem.  Snow will melt into the pond unless there's ice down first.  Ice won't form where water is moving.  You don't want to overstir a small pond which can cool it faster.  If you can se the pump a foot below the water surface, that would help.  At the same time, you want some exchange on the bottom so the fish get enough oxygen which is why I use an air stone in my 153 gallon.  If you send me some photos of your setup (e-mail on my web site), I can give you a more educated opinion.  In general, it's better to have some movement and aeration than none even in the dead of winter.  Good luck!

Robyn
fishpondinfo.com

Answer
The pump has two outputs?  You say one moves the surface which is good.  I don't quite understand; you have another output that goes to the bottom?  I don't think you have too much aeration (no fountaining or air stones) but there could be too much mixing or perhaps too much force on the bottom which could bother the fish.  It's hard to say without seeing it.