Azolla caroliniana
Mosquito fern
Wissenschaftliche Klassifizierung
Reich:Plantae
Stamm:Tracheophytes
Klasse:Polypodiopsida
Ordnung:Salviniales
Familie:Salviniaceae
Gattung:Azolla
Art:caroliniana
IUCN-Status:Nicht bewertet
Schnellstatistiken
Schwierigkeit
Einfach
Umgebung
Süßwasser
Temperatur
20°C - 28°C
pH-Wert
6 - 8
Wasserhärte
36 - 143 ppm
Wachstum
Very Fast
Beleuchtung
Mittel - Hoch
Max. Höhe
1-3 cm
Platzierung
Schwimmend
CO2-Anforderungen
Keine
Wasserströmung
Geringe Strömung
Aquarienbau-Informationen
Max. Höhe
1-3 cm
Platzierung
Schwimmend
Beleuchtung
Mittel - Hoch
Wachstum
Very Fast
CO2-Anforderungen
Keine
Wasserströmung
Geringe Strömung
Substrat
Keine
Befestigungsmethode
floating
Sauerstoffproduktion
Hoch
Abfallreduktion
Hoch
Über diese Art
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Grundbeschreibung
Mosquito fern, also known as Water Velvet, is a tiny floating plant that forms a lush, green carpet on the water's surface. It's an excellent choice for beginners because it is incredibly easy to care for and grows very quickly. This plant is a fantastic natural filter for your aquarium. It works tirelessly to clean the water by absorbing waste from fish and leftover food, which helps keep the water healthier for your aquatic pets. By covering the surface, it provides wonderful shade and a sense of security for shy fish, like bettas, or for tiny shrimp fry to hide among its dangling roots. It also helps prevent algae problems by blocking some of the light and using up the same nutrients that algae need to grow. To care for it, you simply need to float it in a tank with calm water and provide a decent amount of light. There's no need for special plant soil or CO2 gas. Its only real downside is that it grows so fast you'll need to scoop some out every week or so. This prevents it from blocking all the light to plants below and ensures the water surface doesn't get completely sealed off. Its leaves can change from green to a pretty reddish-pink under very bright lights.
Detaillierte Beschreibung
Azolla caroliniana, commonly known as Mosquito Fern or Water Velvet, is a small, free-floating fern highly prized in the aquarium hobby for its rapid growth and powerful nutrient absorption. Its appearance is distinct, composed of tiny, scale-like, water-repellent fronds that overlap along a branching stem, creating a dense mat. These fronds give the plant a soft, velvety texture. Below the surface, it has fine, filamentous rhizoids (root-like structures) that draw nutrients directly from the water column, making it an exceptional tool for managing nitrates and phosphates. This makes it ideal for controlling water quality in heavily stocked tanks or for outcompeting nuisance algae like green water. Hobbyists often use Mosquito Fern in breeding setups, as its dense structure provides excellent cover for fry and a surface for infusoria to colonize, offering a natural first food source. It is also perfect for biotope aquariums mimicking slow-moving streams or ponds, particularly for fish that appreciate subdued lighting and surface cover, such as gouramis, killifish, and wild-type bettas. Propagation is effortless and occurs through vegetative fragmentation; the plant's brittle stems break apart easily, with each piece quickly developing into a new, independent colony. This rapid multiplication requires regular maintenance. It is crucial to thin out the colony periodically by scooping excess plants from the surface. A mat that becomes too thick can severely limit light penetration for submerged plants and, more critically, impede gas exchange at the surface, which could deplete oxygen levels, especially at night. One of the most interesting visual aspects of this plant is its color change. Under moderate lighting, it maintains a vibrant green hue. However, when exposed to intense, direct light, it produces anthocyanin pigments as a protective measure, causing the fronds to blush into shades of red, rust, or deep burgundy, adding a dynamic splash of color to the top of the aquarium. It thrives in still water and should be protected from strong filter outflows, which can submerge and kill the plant; using a floating airline tubing ring can effectively contain it.
Wissenschaftliche Beschreibung
Azolla caroliniana is a heterosporous aquatic fern belonging to the family Salviniaceae. This small, free-floating macrophyte exhibits a highly specialized morphology. The main body is a sporophyte with a floating, branched rhizome that gives rise to bilobed fronds. The dorsal lobe of each frond is aerial, photosynthetic, and covered in papillae that render it hydrophobic. The ventral lobe is submerged, non-photosynthetic, and thinner. The most significant biological feature of Azolla is its obligate symbiosis with the nitrogen-fixing cyanobacterium, Nostoc azollae (formerly Anabaena azollae). This endosymbiont resides within specialized cavities in the dorsal lobes of the fronds, allowing the fern to fix atmospheric nitrogen (N₂). This capability makes A. caroliniana largely independent of dissolved nitrogenous compounds in the water, giving it a profound competitive advantage in nutrient-poor environments and fueling its famously rapid growth rate. This relationship is responsible for its high protein content and its traditional use as a biofertilizer in agricultural systems, particularly rice paddies. Reproduction in an aquarium context is almost exclusively through vegetative fragmentation. In its natural sexual life cycle, the plant produces sporocarps on the ventral lobes. It is heterosporous, producing microsporocarps containing male microspores and megasporocarps containing a single female megaspore. Fertilization results in a new sporophyte, though this process is rarely observed in captivity. Physiologically, its placement at the air-water interface grants it unlimited access to atmospheric CO₂, explaining why injected CO₂ is not required for robust growth. Its high demand for light is linked to the energy requirements of both photosynthesis and nitrogen fixation. The synthesis of reddish anthocyanin pigments under high irradiance is a photoprotective mechanism to shield the photosynthetic apparatus from oxidative damage. Ecologically, the genus Azolla has global significance. The 'Azolla Event,' a paleo-climatological hypothesis, posits that a massive bloom of Azolla in the Eocene Arctic Ocean sequestered vast amounts of atmospheric carbon, triggering a period of global cooling.