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I have a 500-gallon pond with six comets in it. I live in New Jersey, and it's been pretty cold, so the pond has been frozen (except for the heater area) for the better part of the last month.

It's just starting to thaw now, and when I looked at it today, I noticed that there was a lot of really gross gelatinous-looking algea or slime or something in it.

I haven't noticed anything like that in previous winters. Should I try to fish it out with a net or just leave it?

anything that will actually seperate out of the water when it gets cold enough would scare me. Added any additives to the pond this year? Know what all is in your water runoff? I personally would be out there removing it from the water. I know, not a lot of fun.

koi

Empty chairs at empty tables, the room silent, forlorn.

No, I don't add a thing to the pond except for salt. And the pond has enough of a lip that I don't think it really gets any runoff.

It's definitely some kind of algae -- I'm just stunned that it's cropping up now. I'll go out there with the net this afternoon and dredge it out.

Update:

Last weekend, I went to a meeting of the local koi club, and coincidentally the subject on the agenda was "algae."

The speaker, a veterinarian known locally as "the pond doc," is widely respected in scientific circles for the work he's done in the field.


One of the members brought in a sample of her pond water to show him, and it was filled with the exact same green cloudy algae that my pond has at the moment.

According to "Pond doc," it's not as uncommon as most people think, especially because a lot of ponds actually get more sun in winter than they do in summer when the leaves are on the trees.

(The other member had recently added bacteria to her water, which of course died on contact with the cold water and provided decaying organic material that may have fueled the algae growth. But I haven't added anything, and he said the algae could easily spontaneously arise.)

Anyway, he suggested we both test for nitrates (i.e., for evidence of biological activity) and alkalinity (to make sure the water is buffered against algae-caused pH shifts which would be as stressful to the fish at this time of year as they are when they're more metabolically active.)

Presuming both of those are within reason -- nitrates should be under 25, he said -- then he suggested both the other member and I leave the algae alone.

If nitrates are high, he suggests a small water change, even at this time of year. And if the water's buffering capacity is low, he says to correct that immediately since it's as problematic at this time of year as it is at any other time. He said he usually recommends baking soda for that.

He feels pretty firmly that algae is a necessary part of the pond ecosystem, and that anything you do to it effects the balance of everything else -- even at this time of year. (If it's gone so wild that you can't see the fish in summer, he agrees that it needs to be controlled, but says that

So I'm going to run a couple of water tests today. I thought it was interesting, because water tests aren't something most pondkeepers do in the winter, and he thinks it's a good idea, since all the rain and snow can drastically alter the pH but more importantly the buffering capacity.

Anyway, just thought other members people might find that info useful as I did!

a lot of ponds actually get more sun in winter than they do in summer when the leaves are on the trees.

I would never have thought of that! Although it doesn't get cold enough where I live for the freezing of ponds so it is all news to me that concept of frozen water (fascinating to me)

Although the same principle is used in designing a garden. People purposely plant trees in front of windows that will shade them in summer and in winter let the light through to the house as there are no leaves. Same principle with the ponds...it just would never have occurred to me.

Great post. Am sure lots of others appreciate your sharing the info you got from the doc!

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