This is Bacopa monnieri.

Nice plants everyone. So glad to see the Malaysian aquatic plant scene taking off.

I'm also a bit confused with the eichhornia/ heteranthera debate. My heteranthera has a more pointy leaf tip. Then again, I've always known eichhornias to have a 2 dimensional profile, ie. 2 rows of leaves on two sides, not star like.

The red stem plant from hans.excel is ludwigia brevipes. It is always confused with didiplis diandra as they both have similar leaf stucture/colour. To compare, didiplis has the presence of small 'bulges' which looks very much like buds on most nodes. L.brevipes does not.