I think it's
Hygrophila pinnatifida
http://www.tropica.com/en/plants/plantdescription.aspx?pid=051A
I used APC's Plant Finder to narrow it down. I thought Id had one. I knew it had pinnati...in the name LOL.
http://www.aquaticplantcentral.com/forumapc/plantfinder/all.php
It's Hygrophila Pinnatifida.