The one on the top confuses me a little bit because of its alternate leaf arrangement. Is it new in your tank? I think submersed foliage (if that is not it) will help out a lot. My first instinct was Ludwigia glandulosa, but the green color sort suggests otherwise.
The second one I think is an Alternanthera, probably reineckii 'Red'. Where did you find it? It also looks a lot like my Alternanthera ocipus.