The plant in the front is Echinodorus amazonicus or amazon sword. There is another common amazon sword (Echinodorus bleheri) but it has slightly wider leaves and more stalk before the leaf forms. The plant at the top/rear is Hygrophila corymbosa stricta (also known as H. stricta, temple plant and blue hygrophila). Wen it gets too tall you cut it off above the bottom two leaves and replant it. The stump will often produce two branches and the cutting grows roots so that one becomes three.