ID this plant?

[celtic11]

Could someone ID this plant for me? I have two of them in my tank and while they aren't dying, they don't seem to be thriving. I did some research on Google and thinking maybe water sprite?

 

[celtic11]

Here is the picture.

 

[aqua_chem]

Hard to be 100% certain from that photo, but it looks like water sprite (Ceratopteris thalictroides) to me. It could also be water wisteria (Hygrophila difformis), but without better resolution of one of the leaves, I'm not completely sure.

 

[Mebbid]

I'm almost positive that it's water sprite. From my experience the water wisteria doesn't grow the root balls up on the stems like that plant appears to be doing.

 

[foster53]

That's Watersprite.