The Java Fern (Microsorum pteropus) is a resilient plant for aquariums, known for its adaptability to various water conditions. Unlike many aquatic plants that root directly into the substrate, the Java Fern has a unique structure called a rhizome, which is a thick, horizontal stem. This biological characteristic requires a different installation technique than simply burying it in gravel or sand. Understanding how to handle and secure the rhizome is the foundation for successfully integrating this plant into an aquascape.
Preparing the Java Fern for Planting
Before securing the Java Fern, it needs careful preparation to ensure optimal health and attachment. If the plant was purchased in a pot, gently remove all fibrous packing material, such as rock wool, from the roots and rhizome. Cleaning off any residual debris or old, damaged leaves provides a clean surface for attachment and prevents potential decay in the aquarium.
The rhizome is the thick, horizontal section from which both the roots and leaves sprout. If the specimen is a large clump, dividing the rhizome into smaller segments, each containing a few leaves and roots, promotes better growth and allows for broader placement within the tank. Use clean, sharp scissors to cut the rhizome, ensuring each piece is robust enough to establish itself.
The fine, dark strands extending from the rhizome are the roots, which function primarily as holdfasts to anchor the plant to surfaces, rather than for nutrient absorption from the substrate. Trimming excessively long or tangled roots by about one-third can encourage the development of new, stronger roots that will quickly grip the chosen hardscape. This trimming should only focus on the thread-like roots, leaving the main rhizome structure completely intact.
Safe Attachment Methods
Since the rhizome must not be buried, the Java Fern is secured to hardscape elements like driftwood, rock, or decorations. One of the simplest and most effective methods is the use of cyanoacrylate-based super glue, which is aquarium-safe and cures almost instantly upon contact with water. Applying a small dab of the gel-formula glue directly onto the desired attachment point on the hardscape allows the rhizome to be pressed firmly against it for a few seconds until the bond sets.
Another reliable technique involves tying the plant onto the hardscape using materials such as cotton thread, fishing line, or specialized plant thread. The string should be wrapped snugly around the rhizome and the object, holding the plant in place without crushing the main stem. Over a period of several weeks to months, the plant’s roots will naturally anchor themselves to the surface. Biodegradable cotton thread will eventually disintegrate, leaving the plant permanently secured.
A third method utilizes the natural crevices and holes found in driftwood or porous rocks. The rhizome can be lightly wedged into a gap, securing it just enough to prevent it from floating away. This approach is non-invasive and allows the plant to naturally grow its roots into the hardscape’s pores. Regardless of the method used, the goal is always to keep the central, horizontal rhizome exposed to the surrounding water column.
Protecting the Rhizome and Initial Care
The rhizome must remain exposed to oxygenated water and should never be buried in the substrate like gravel or sand. If buried, the rhizome will be deprived of necessary oxygen, leading to anaerobic conditions that cause it to rot and ultimately kill the plant. This is the most common mistake new aquarists make when introducing this species.
After attachment, the plant’s initial placement should consider both light and water flow. Java Fern thrives in low to moderate light conditions, and excessive light intensity can cause the leaves to develop brown spots or “melt.” Positioning the plant where it receives a gentle current is also beneficial, as water flow delivers nutrients directly to the leaves and exposed rhizome, preventing stagnant water conditions that can encourage algae growth.
During the transition to a new aquarium environment, some older leaves may experience a period of melting. Pruning any leaves that turn black, brown, or become translucent will direct the plant’s energy toward producing new growth. Healthy new plants, often called plantlets, will eventually sprout from the leaves, indicating successful acclimatization and a thriving environment.