Hornwort (Ceratophyllum demersum) bunch

Ceratophyllum demersum, known worldwide as Hornwort, is one of the most widely sold, most adaptable, and most useful aquarium plants ever brought into the hobby. Its dense whorls of fine, bristle-like dark green leaves grow rapidly under almost any conditions — low or high light, hard or soft water, heated or cold water — making it one of the few truly universal aquarium plants. It produces allelochemicals that actively suppress algae growth in the water column, helping maintain clarity in new and established aquariums. Its thick, branching stem growth creates the ideal dense refuge for egg scattering fish, fry, shrimp, and small invertebrates. It can be planted in substrate or left free-floating. An indispensable, inexpensive, and endlessly useful aquarium plant found in virtually every Belgian and Dutch shop.

Plant loosely in substrate or float freely. No CO2, fertilization, or special substrate required — grows robustly on ambient nutrients. In bright light it grows very rapidly; trim regularly to prevent overgrowth. Note that Hornwort sheds its lower leaves when lighting or parameters change, creating some temporary debris — this is normal. Extremely adaptable to temperatures from 10°C to 28°C. An excellent plant for cycling new tanks, breeding tanks, and community aquariums at any experience level.