Anubias is a genus of hardy aquatic plants popular in the aquarium hobby due to its robust nature and tolerance of low light conditions. While you can place the plant in the substrate, a critical distinction must be made regarding its anatomy. If the thick, horizontal stem, known as the rhizome, is completely buried, the plant will almost certainly rot and die. This requirement is the most important factor for keeping Anubias healthy.
The Critical Anatomy: Understanding the Anubias Rhizome
The survival of the Anubias plant revolves around its rhizome, which is a modified stem that grows horizontally. This fleshy structure is the plant’s primary storage organ, holding reserves of starches and sugars. All leaves, roots, and new growth buds sprout directly from this central stem.
In its natural habitat, Anubias grows as an epiphyte, attaching itself to rocks and driftwood with the rhizome exposed to flowing water. This adaptation means the rhizome is not designed to be encased in an anaerobic or low-oxygen environment like submerged soil or gravel. Covering it with substrate prevents necessary gas exchange and encourages anaerobic bacteria.
The resulting condition is rhizome rot, where the tissue turns soft, mushy, and discolored, eventually killing the plant. A healthy rhizome should be firm and pale green or white, remaining above the substrate line for continuous exposure to oxygenated water. To successfully “plant” Anubias, the roots can be tucked into the substrate, but the entire rhizome must remain fully exposed to the water column.
Anchoring Methods for Anubias
Since the primary growth structure cannot be buried, securing Anubias requires alternative anchoring methods to keep the plant in place. These techniques mimic the plant’s natural tendency to attach to hard surfaces, holding it steady until its roots establish a grip. The goal is to provide temporary stability without damaging the delicate rhizome tissue.
One popular and discreet method involves using cyanoacrylate, a common aquarium-safe super glue, typically in a gel formula. After briefly drying the rhizome and the chosen hardscape, a small dab of gel is applied to the underside of the rhizome and pressed firmly onto the wood or rock for about 30 seconds. The glue cures almost instantly upon contact with water, creating an inert bond that securely holds the plant.
A more traditional approach utilizes dark cotton thread or thin fishing line to physically tie the rhizome to a piece of driftwood or lava rock. Wrap the material snugly around the hardscape and over the rhizome, taking care not to constrict the stem too tightly, which could cause damage. Over a period of several weeks to months, the plant’s roots will naturally grow and attach themselves to the textured surface, at which point the temporary thread can be carefully snipped and removed. Hobbyists also find success by gently wedging the plant into crevices or holes found in porous rocks or wood, ensuring the roots are directed into the opening while the rhizome remains outside the gap.
Substrate and Nutrient Delivery
The roots of the Anubias plant serve a different function than those of many other aquatic species. For Anubias, the fibrous roots are primarily for physical attachment to hard surfaces, providing anchorage against water currents. These roots can be safely buried in the substrate (sand, gravel, or soil), as long as they are only anchoring the plant and not covering the rhizome.
While the roots are capable of minor nutrient uptake from the substrate, Anubias is predominantly a water column feeder. The plant absorbs the majority of nutrients directly from the surrounding water, primarily through its leaves and exposed rhizome. It is highly efficient at utilizing dissolved nutrients, such as nitrates and phosphates, naturally present from fish waste and food breakdown.
To maximize the health and growth rate of Anubias, the most effective fertilization strategy is regular dosing of a comprehensive liquid fertilizer into the water column. Unlike heavy root feeders, this plant does not typically require the use of root tabs buried in the substrate. Supplying nutrients directly to the water ensures they are immediately available for absorption through the plant’s leaves, supporting its slow but steady growth habit.