Anubias species are a popular and hardy choice for freshwater aquariums, known for their deep green foliage and resilience. They thrive in various tank conditions, making them excellent for beginners and experienced hobbyists. Anubias cannot be planted in the substrate like typical rooted plants. While the roots can be buried, the main stem structure must remain exposed to the water column to ensure its long-term health.
Understanding the Anubias Rhizome
The reason for this unconventional planting method lies in the plant’s unique anatomy: the rhizome. This thick, horizontal stem is where the leaves and roots emerge, serving as the plant’s main structural support and storage organ. Unlike plants with vertical stems, the Anubias rhizome grows along a surface. If completely buried beneath the substrate, it becomes deprived of necessary oxygen and water flow, causing the stem to suffocate and degrade. As an epiphyte, Anubias draws nutrients primarily from the water column rather than the soil.
Securing Anubias to Hardscape
Since the rhizome must not be buried, Anubias plants are best secured to hardscape materials such as driftwood or porous rock. The goal is to hold the plant in place until its roots naturally anchor it to the surface. One effective method is using cyanoacrylate gel super glue, which is aquarium-safe once cured; apply a small dab of gel and press firmly for 30 to 60 seconds. Alternatively, use cotton thread or fishing line to carefully tie the rhizome to the hardscape, ensuring the material is snug but does not damage the stem tissue. The roots can dangle freely or be guided into the substrate, but the rhizome must remain fully above the surface until the roots grow onto the hardscape, creating a strong anchor.
Recognizing and Preventing Rhizome Rot
Improper planting, particularly burying the rhizome, can lead to rhizome rot. Symptoms of this bacterial or fungal decay include a blackening or browning of the tissue. A healthy rhizome is firm and green, but an infected one will feel soft or mushy. Proper placement is the primary prevention, ensuring the rhizome is never covered by gravel or sand, which fosters the low-oxygen environment that causes rot.
Treating Rhizome Rot
If these signs appear, immediate corrective action is necessary. Remove the Anubias and use sterilized scissors or a sharp blade to trim away all affected tissue. The cut must extend into the firm, healthy part of the rhizome to ensure complete removal of the decay. After trimming, reattach the plant to hardscape and place it back in the aquarium with the fresh cut exposed to clean water flow.
Essential Care for Long-Term Health
Once Anubias is correctly secured, its long-term health depends on simple, consistent care. This species thrives in low to moderate light conditions, requiring 8 to 10 hours of light per day. Intense lighting promotes algae growth on the slow-growing leaves, which can starve the plant of light. Good water movement around the exposed rhizome also helps deliver oxygen and nutrients directly to the stem.
Fertilization
While Anubias absorbs nutrients from the water column, supplemental fertilization is beneficial for robust growth. Liquid fertilizers provide necessary micronutrients and macronutrients, absorbed by the leaves and rhizome. If using root tabs, place them near the roots in the substrate, but never directly touching the exposed rhizome.