as another example about crypts, I have a bunch doing quite well as a floater. It was a trim from another tank but I ended up just not replanting it, and it's doing just fine. I think it's a green wendtii, but all the new leaves come out a very pretty pink since it's sitting about 3 inches directly under the light. A second neat consequence is some java moss that was stuck around the roots has filled out as well into a puffball. The shrimp love it. This tank is basically a walstad/low tech with a strong light. I don't dose anything except feeding the fish and the substrate is small rock gravel. But it's also light on plants at all, just glosso and a few anubias with a single madagascar lace.