Boreal lakes on both sides of the North Atlantic: Scandinavia, west and north Britain, Iceland, the Faroes, Poland to NE France; Bulgaria
Water
freshwater
Temperature
4–18°C
Care level
expert
Care
Lake quillwort or Merlin's grass is a spore-bearing relative of the club mosses from cold lakes on both sides of the North Atlantic, including Scandinavia, the west and north of Britain, Iceland and the Faroes, with isolated populations in glacial lakes in Bulgaria's Pirin mountains. It forms a rosette of stiff, quill-like leaves from a small corm. Our sources say nothing about keeping it. It is a plant of cold, clear, nutrient-poor water and does poorly in warm tropical tanks; it suits only a cool, unheated tank or a specialist set-up. Temperature is our estimate, not from the sources. Never collect it from the wild. Sources: Wikipedia (en.wikipedia.org/wiki/Isoeteslacustris); Wikipedia, List of freshwater aquarium plant species. Checked October 2026.
Breeding
Quillworts reproduce by spores formed at the leaf bases; our sources give no details for cultivation, and it is rarely propagated in aquariums.
Compatibility and tank mates
Only for unheated, coldwater set-ups with small, gentle fish; diggers will uproot it.
Last updated 8 October 2026. Community-edited care guide on Aquatic-Auctions.
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