Blyxa japonica is a compact, grass-like foreground plant that forms a rosette of narrow, slightly arching leaves in a warm yellow-green to deep green colour. Made famous by Takashi Amano's iconic natural aquascapes, it remains one of the most effective foreground plants for this style of layout — the leaf texture and form are genuinely unlike anything else in the planted tank world.
It has a reputation for being demanding, but in practice medium lighting and CO2 are the main requirements and it performs well once these are in place. Under high lighting it can develop attractive red tones across the leaves. Unlike carpeting plants, it doesn't spread aggressively — it forms discrete clumps, which gives you control over placement without constant trimming.
Plant into the substrate as a foreground or lower midground specimen and leave it to establish. A group of clumps creates excellent impact. As this is grown underwater, invertebrates may occasionally be present; a preventative dip is recommended if you have sensitive tanks.