Isoetes malinverniana

Isoetes malinverniana is found only in the Ticino and Po rivers in northern Italy and is critically endangered in the wild, making its cultivation in the aquarium hobby a genuine act of botanical conservation. It produces longer, more flexible and graceful quill-shaped leaves than I. lacustris, arranged in a spreading fountain rosette. Like all Isoetes it requires cool, very clear, soft water with bright light and CO2, placing it firmly in the specialist category — but its rarity and beauty justify the effort.

Light: High (>60 PAR at substrate); essential for corm health and leaf production. CO2: Required; 20–30 mg/l supports the CAM-photosynthesis mechanism. Planting: Plant the lobed corm at the substrate surface in fine, low-nutrient gravel; do not bury the growing tip. Maintenance: Very slow-growing; patience is essential — remove damaged leaves only. Note: Cool, clear, soft water (15–20°C) is non-negotiable; conservation of this critically endangered species is a genuine bonus.