What's this plant?

Yesterday I found a plant that I cannot identify.  I have seen it a
couple of times before.  The general appearance is like that of
Didiplis diandra (same size, same kind of leaves, etc.), but the
leaves are a bright red.  It was beging sold as a species of Rotala,
but it is definitely not R. rotundifolia, R. macarandra or R.

I did not buy it this time around, because I don't think my tank is
bright enough to keep it alive.  So, what is this plant?  Has anyone 
managed to cultivate it successfully?

They also had single potted Crypt. petchii for $6.99 apiece (ouch!).