Just bought this red plant at a local fish store at just $2. I am thinking it is Ludwigia repens (or possibly other type of Ludwigia).
Red plant (Ludwigia repens?) in low tech 5 gallon tank. No CO2. I bought this red stem plant for my fish to celebrate Chinese New Year. Hope it can survive in my tank!
Update: Unfortunately, upon further research, the above red plant may actually be Alternanthera sessilis which is not aquatic! The stems and leaves of the above said plant are quite hard and stiff, which is characteristic of a terrestrial plant.
I have tried to ask experts on the Planted Tank Forum, they have confirmed that it is not Ludwigia arcuata (which I originally thought it was).