Proserpinaca palustris, which is commonly called Mermaid weed in the industry, can be found in both North and South America. It is a typical high demand plant preferring high light, high CO2 and good access to nutrients. Given these demands, it is not a difficult plant to grow. Intense light...
www.2hraquarist.com
View attachment 191523
anyway, since its still green, maybe these are still the emersed leaves? The submersed leaves should be red if you have enough light. If these are submersed leaves, then they are quite "thin" who according to 2hr aquarist, it is lacking either CO2 or nutrients.
when I had it in my old tank, I got the emersed version, but it turned red pretty fast at the top. The bottom leaves the colour is not as nice.
in the end i didn't find the plant suitable - like the 2hr aquarist writeup points out, it spreads out its branches and takes a lot of space but is the leaves are quite spaced apart. I've switched instead of Myriophyllum 'Roraima'/ 'Red Stem' because they have much finer and densely packed leaves and so it makes a better 'bush' that Mermaid weed.