Crown and Stem Rot

For epiphytes and rosettes: seemingly healthy, green leaves detach and float upwards with a black, mushy base. The rhizome turns into foul-smelling mush. For stem plants: the lower part of the plant blackens, becomes stringy, and breaks off, unmooring the entire plant from the substrate and causing it to float to the surface ('floating stem').

For epiphytes and rosettes: seemingly healthy, green leaves detach and float upwards with a black, mushy base. The rhizome turns into foul-smelling mush. For stem plants: the lower part of the plant blackens, becomes stringy, and breaks off, unmooring the entire plant from the substrate and causing it to float to the surface ('floating stem').

Mechanical and asphyxic rot of the stem or rhizome commonly occurs due to human error during planting, not nutritional deficiencies. When rosette or rhizomatous plants (like Anubias, Microsorum, Bucephalandra) are planted too deeply, burying the 'crown' or rhizome in the sand or soil, the soft tissues drown and rot. In stem plants (Rotala, Ludwigia), planting too many stems bunched together in a single hole deprives the lower portions of light and oxygen, causing them to blacken and snap.

Compare sign distribution, leaf age, mechanical damage, emersed-to-submersed adaptation, algae, pests and multiple concurrent deficiencies.

Confirm with a photographic timeline, repeated measurements and one controlled change at a time; an isolated leaf sign does not automatically identify the cause.

Stabilize light, CO₂, temperature and water quality; remove only decaying tissue. Avoid concentrated corrections or several simultaneous changes.

Immediately remove the plant from the substrate. With sharp scissors, completely cut away the black rotting part of the rhizome or stem until reaching firm, living white/green tissue. Rot spreads very quickly like a necrotic infection. Replant healthy stems individually, leaving a few millimeters of space between them for light and water flow penetration.

When buying a pot of stem plants, remove all the rockwool, patiently separate every single stem, and plant it with curved tweezers, spacing them about 1 cm apart ('mosaic method'). Rhizomatous plants (Anubias, Ferns) should be tied to rocks or driftwood using fishing line or cyanoacrylate gel glue, ensuring the rhizome runs free above the substrate.

When buying a pot of stem plants, remove all the rockwool, patiently separate every single stem, and plant it with curved tweezers, spacing them about 1 cm apart ('mosaic method'). Rhizomatous plants (Anubias, Ferns) should be tied to rocks or driftwood using fishing line or cyanoacrylate gel glue, ensuring the rhizome runs free above the substrate.

Escalate if deterioration is rapid, involves the rhizome or stem, produces foul odor, or coincides with animal distress or detectable ammonia/nitrite.