Java Moss is an unusual plant because it does not have roots to speak of, will sink to the bottom, will grow like weeds under the crappiest conditions (no gravel, low light, no fertilizer, most water temp ranges and most PH ranges) and doesn't look too shabby either ;).
What's most is, the Moss loves stagnant water and lots of nitrite. In fact it will THRIVE on high nitrite levels and left over food and fish fecal matters.
Create a lush and textured appearance in your aquarium with Java Moss. This plant features dense, green foliage that grows in clumps and provides excellent hiding spots for fish and fry. Attach it to rocks, driftwood, or mesh using fishing line or simply let it float in the water. Java Moss is undemanding and can thrive in a wide range of lighting conditions. Care Instructions: Low to moderate lighting and regular trimming. Tips: This plant can be used to create a carpet effect or as a natural filter for your tank.