Thank you all for identifying this weed, can anyone tell me will it harm the fish I mean would they be able to breathe with the water covered in this weed.

The problem with duckweed is that it shades the pond which stops the oxygenators working..



Andy


Fly fishing North Yorkshire

If it covers the water surface entirely it can cut off the oxygen transfer between air and water. If that happens fish will die.

Mmmm thanks for the replies, bad news that though I guess it makes sense if it covers it right over like it does, pain really as it is a nice pond well lake really used to have some good fish in it too, but was never very deep and guess that does not help either oh well, but at least I know now what the rotten old weed is called gets lots of ducks on it too and is home to some good wildflife too. Thanks for all you help . . .

Worse still it is easily transferred to other waters by ducks, boats and anglers waders

Yeah bad news it is a real pest as it is a good lake and looks great now you can see the water but that will get covered come summer and all you see is a green mass and no water to be seen at all, it does get many ducks on it too so maybe they brought it in .

We sometimes use duck weed in wasterwater treatment plants for various reasons, ducks like to be in the basins covered with duck weed, however, you would need a LOT of ducks to clear it. In fact, the basins i am talking about have a lot of ducks but there is no vidible effect. Of course if you would create a huge concentration of ducks, you would have a nutrition input by the ducks, so you might get algal bloom. If you introduce grass carp, you are on a good way to algal bloom too.

BlueOne