Help with Plant Identification

Hi all,

So I got a piece of plant from my LFS when I bought my RCS. The plant has grown, and I like it, but after several attempts of trying to identify it, I still don't know what it is. It may be some type of floater, as it's in a low flow tank, yet it pieces still seem to "break off". Just to experiment, I tied a few pieces to some rocks to see what would happen. As you can see, they are doing fairly well. The tank is by a window that faces East. It gets a little direct sunlight in the morning, but not much. It does get a good amount of ambient light however.

Any help is GREATLY APPRECIATED!

I thought that a type of moss was a possibility. That's kind of why I attached it to the rocks and see if it did better on the rocks. It definetly does not like them. It grows toward light, upward, and like I said, pieces are almost released from it to float. I have been leaning toward guppy grass. I just haven't found any photos like this.