Salvinia? if it's got quite big leaves.
Hopefully it's not azolla because you'll never get rid of it all.
If it's not these I'll have another think.

Thinking cap on again, please!

It's certainly not Salvinia.

Each 'goose' measures just over half an inch and is very flat and lightweight.

I've checked out pictures of various types of Azolla but I can't see it there. I've been fishing it out as much as I can because I don't like things like this and duckweed because they take over.

Try Lemna trisulca or ivy leaved duckweed.

Spot on again! Don't know how you do it, but thanks.

Interesting that it's of the duckweed family, but it is a lot easier to fish out. I also quite like it in a funny kind of way, but I just don't want it to take over.

I think I prefer my description of flying geese or maybe even those flying ducks that were on the wall in Coronation Street!