WANTED: Low co2 plants

Any good plant suggestions for a uk koi pond. A few months old. I put 5 lillies potted in there and a few water soldiers. A large male koi destroyed the lillies . Maybe a larger type of plant required?

Anyone in cumbria have any live plants they want rid of many tks

Cant stop my small pond going green in a few days tried many things got plants a box filter plus a small filler any help plz will a uv light do it

Anyone any water lettuce?