I've only seen duckweed a couple of times so am no expert. However, it is my understanding that it is extremely undesirable. It always comes as an infestation. Plants "generate" O2 during the day but absorb it at night. It always comes as an infestation.

So, to me, step one would be to spray the weeds prior to stocking anything.

It's not about the fish. It's about the pond. Take care of the pond and the fish will be fine. PB subscriber since before it was in color.

Without a sense of urgency, Nothing ever gets done.

Boy, if I say "sic em", you'd better look for something to bite. Sam Shelley Rancher and Farmer Muleshoe Texas 1892-1985 RIP Grandpa