Süsswassertang

Lomariopsis cf. lineata

Also known as Subwassertang, Round pellia, Coral pellia, Freshwater seaweed, Lomariopsis lineata

FreshwaterMossRhizome division

Süsswassertang (Lomariopsis cf. lineata) — Rǫgn · CC BY-SA 4.0

Care at a glance

Light: Low light
CO2: No CO₂ needed
Growth rate: Slow
Placement: Epiphyte
Type: Moss
Temperature: 64–82°F (18–28°C)
pH: 5.0–7.5
Hardness: 0–8 dGH
Max height: 2 in (5 cm)
Spread: 5.9 in (15 cm)
Nutrient uptake: Water column
Growth region: Submersed
Difficulty: Easy
Origin: Tropical Southeast Asia (exact wild origin uncertain; all aquarium stock is thought to descend from a single clone discovered in cultivation around 2001)
Family: Lomariopsidaceae

Overview

An undemanding, shade-tolerant plant for low-tech tanks. It does not root, so wedge it into driftwood crevices or tie it to wood or stone and let it secure itself, or just leave loose clumps for shrimp and fry to hide in. Low to moderate light suits it, no CO2 is needed, and growth is slow, so it rarely needs trimming. Strong flow tears off and scatters pieces, so keep it in calmer water.

In the wild

The wild source is unknown, and all aquarium plants are believed to be clones of a single specimen that botanist Christel Kasselmann found growing in cultivation around 2001. It is most closely linked to a tropical Southeast Asian fern. In the tank it forms loose, lettuce-like translucent green clumps that drape over hardscape rather than rooting.

Good to know

For years aquarists assumed Süsswassertang was a liverwort, but a 2009 molecular study showed it is actually the gametophyte (the haploid, leafy stage) of a fern, most closely related to Lomariopsis lineata. It is sold and grown only in this gametophyte form, and attempts to make it produce a sporophyte have failed, so it is often written as Lomariopsis cf. lineata to flag that uncertainty.

Did you know

Did you know Süsswassertang is one of the very few aquarium 'plants' that is a fern gametophyte? It is the same life stage that, in a normal fern, is a tiny short-lived heart-shaped scrap, except here it grows indefinitely without ever maturing into a leafy fern.