Can't see our pond, Rose, it's covered in ice with snow on top. I hope the fish have the sense to bury themselves into the mud. We have had the same 16 for 6 years now, it would be sad if they all freeze. I have given some names as well.
I said to OH about the cardboard, but he said the same, if it moved it would frighten them away, but I am noticing that where the birds are foraging for food on the grass they are clearing away the snow. The Redwings know exactly what to do & the other birds benefit from it.