Riccia Fluitans (Crystalwort)

Riccia fluitans is a liverwort that grows natively all over the world, popping up in ponds, ditches, and slow-moving streams across multiple continents. In its natural state it just floats in tangled mats at the surface, which is honestly how it's happiest.

What made it famous in the aquarium hobby was Takashi Amano's idea to tie clumps of it down to rocks and driftwood, creating that iconic bright green foreground carpet absolutely loaded with pearling oxygen bubbles under strong light. It's a stunning effect.

The plant itself is bright lime green, growing in dense, branching thalli rather than true leaves, and under good light it pearls intensely even without CO2. CO2 does push growth and color noticeably though.

The catch with keeping it tied down is maintenance. It grows fast and the lower portions die off as light can't penetrate, so you'll be trimming and retying regularly or it detaches and floats away. Used as a floating plant, it's far lower effort and still looks great.

Many aquascapers lean into the floating use for shaded breeding tanks or shrimp setups. If you want inspiration, searching 'Riccia fluitans iwagumi' will pull up some jaw-dropping builds.