Hygrophila polysperma is one the easiest plants to grow, suited for beginners and new set ups as it just keeps growing whilst absorbing excess nutrients. Originating from India, the polysperma grow very fast and often need trimming. Under good lighting the shoot will turn a reddish-brown.
When planting this plant in the substrate try using 2 or 3 rocks to surround the stem, this will highlight the plant and help bring out the colour.