Just place a dab of super glue gel on the rock, wood, or other object where you want the fern to grow. Then, press the Java fern's rhizome, or the horizontal, stem-like structure below the leaves, onto the glue for 30 seconds. Let the glue dry for 15 to 20 minutes, then place it in your aquarium. Java Moss Stats. Minimum Tank Size: 5 Gallons. Care Level: Very Easy. Water Conditions: 5.0 - 8.0 and Soft to Hard. Temperature: 18-30 °C (70-75 °F) Java Moss ( Vesicularia dubyana) is one of the easiest to grow of all the commonly available aquatic plants. It's hardy nature and striking green coloration makes it a favorite among aoXtf.