Landoltia punctata

Species description

Care, breeding and tankmates

Plant profile

Placement

Floating

As a free-floating aquatic plant, it occupies the water surface of the aquarium. It should be used strategically, as it can quickly form a dense mat that blocks light from reaching submerged plants. It is often kept in isolated floating rings to prevent it from covering the entire surface.

Botanical form

Floating

Also known as dotted duckweed, it consists of small, oval-shaped fronds that float on the water surface. Each frond is somewhat thicker and slightly larger than common duckweed (Lemna minor) and typically features two to several short roots dangling beneath. The fronds have a bright green topside and often a reddish or purplish underside.

Growth

very-fast

This plant has an extremely fast, almost explosive growth rate under favorable conditions. It multiplies continuously by producing new fronds, capable of doubling its population in just a few days. Frequent and aggressive removal is usually necessary to keep its population in check.

Substrate

None

Landoltia punctata, also known as dotted duckweed, is a strictly free-floating aquatic plant that requires no substrate whatsoever. It utilizes its fine, dangling roots to absorb nutrients directly from the water column rather than from the aquarium floor. Substrate composition and depth are irrelevant to this species, as it completes its entire life cycle floating on the water surface.

Column fertilization

Required

It relies entirely on water column fertilization, absorbing all necessary nutrients directly through its floating fronds and dangling roots. It is an excellent biological filter, quickly taking up ammonia, nitrites, and nitrates. Additional fertilization is rarely needed unless the tank is heavily planted and nutrient-depleted.

Root fertilization

None

Because it is a strictly floating plant, it does not interact with the substrate and therefore does not require root fertilization. All nutrient uptake occurs from the surrounding water. Its dangling roots provide a large surface area for this purpose.

Trimming

Regular

Trimming is not applicable; instead, maintenance involves manually scooping out excess plants with a net. It is important to remove large portions of the mat regularly to ensure sufficient light penetrates the water for submerged species. Care must be taken to remove even tiny pieces if eradication is desired, as they regrow rapidly.

Propagation

Division

Propagation occurs naturally and constantly through vegetative budding. New fronds grow from the edges of mature fronds and eventually break off to form independent plants. No human intervention is required for it to multiply rapidly.

Sensitivity

low

It is an incredibly hardy and adaptable plant, tolerant of almost any water parameter, temperature, or lighting condition. It is virtually indestructible in a standard aquarium setting. The only things that generally hinder its growth are strong surface agitation or a complete lack of nutrients.

Layout role

Floating

Its primary role is providing shade for low-light setups and acting as a powerful natural filter to manage excess nutrients. The trailing roots offer excellent hiding places for fry and small shrimp. However, its use in high-tech aquascapes is limited due to its tendency to block essential light from reaching the foreground.