01
Overview
Azolla is remarkable botany in miniature: each frond hosts symbiotic cyanobacteria that fix nitrogen from the air, which is why rice farmers have grown it as living fertilizer for centuries. In aquaria it forms crinkled mats that flush crimson under strong light or cool temperatures.
Size note: Aquarium growth is often moderate, while favorable outdoor conditions can produce rapid mat expansion.
02
Aquascaping use
Its velvet texture and seasonal red suit open-topped, natural-style setups and outdoor mini-ponds. Indoors it stays politer than its outdoor reputation suggests.
03
Planting
Float a patch on quiet water; fragments bud into new plants continuously. It prefers still corners over flow lines.
None
04
Light & CO₂
Bright light triggers the red anthocyanin blush; shade keeps it soft green. Its nitrogen partnership means it thrives even in sterile water.
05
Substrate & fertilization
Effectively self-sufficient for nitrogen and modest about the rest. It grows in water most floaters find too clean.
Feeding behavior: Water-column feeder. Nutrient demand: moderate.
06
Growth, trimming & propagation
Skim excess regularly; mats thicken into light-proof felt if ignored. Dispose thoughtfully, as it colonizes waterways in mild climates.
Fragmentation
07
Common problems
- !Can shade densely once matted
- !Dislikes hot tropical water long-term
- !Invasive outdoors in temperate regions
