Yes, that looks like l. arcuata emersed form.
Also, stargrass will grow like a weed once it gets used to your setup. Idk so much about what to do about the algae though. It's definitely one of my favorite plants though. This photo was from a couple months ago, before I did a little bit of rearranging, thinning out, and trying to control an algae outbreak as well, but this is probably the best I have gotten it to look, I just haven't gotten it back to that level yet. I just had to have the genius idea to move it to a different spot just at the time all the other problems hit. Lol. It's the one on the left behind the blyxa japonica.