I have tried to grow it submerged but haven't had any luck so far. A few died and a few have not really changed 2 weeks. Is it even possible to put in a tank. I have found pictures of it being done but not sure if its possible.
http://www.aquahobby.com/garden/e_Hydrocotyle_verticillata.php
http://www.aquahobby.com/garden/e_Hydrocotyle_verticillata.php