Hornwort
Ceratophyllum demersum
An almost indestructible feathery stem plant that can be planted or left floating, soaks up nutrients fast and gives fry brilliant cover.
| Care Difficulty | Beginner |
| Lighting | Low to High |
| CO2 Requirement | Not required |
| Growth Rate | Very Fast |
| Placement | Background/Floating |
Overview
Hornwort (Ceratophyllum demersum) is an almost indestructible feathery stem plant that can be planted or left floating, soaks up nutrients fast and gives fry brilliant cover. It is a beginner-level aquarium plant, making it a great choice for beginners and low-tech tanks.
This guide covers how to grow Hornwort successfully - its appearance and growth habit, lighting needs, whether it needs CO2, fertilising, planting and placement, propagation, and the common problems to avoid.
Appearance & Growth Habit
An almost indestructible feathery stem plant that can be planted or left floating, soaks up nutrients fast and gives fry brilliant cover.
It is a very fast grower used in the background/floating of the aquascape. Fast growth means regular trimming, but it also makes the plant a powerful nutrient sponge that helps starve out algae.
Lighting Requirements
Hornwort grows best under low to high lighting. Low to medium light keeps it healthy without fuelling algae, so a basic quality LED is plenty.
Run lights on a timer for about 6-8 hours a day. Longer photoperiods usually feed algae rather than plants, so increase duration cautiously and watch for any green film.
CO2 & Fertilisation
CO2: Not required. It grows perfectly well without pressurised CO2, which makes it ideal for low-tech setups.
Dose a balanced liquid fertiliser (such as API Leaf Zone) for water-column nutrients. Yellowing, holes or stunted leaves usually signal a nutrient deficiency, not disease.
Planting & Placement
Plant or attach Hornwort in the background/floating. Plant small portions into the substrate, spacing them so they grow together over time.
Propagation
Snap off any side shoot or healthy length of stem and it keeps growing - trim regularly to control it.
Sharing trimmings is part of the fun of the hobby - one healthy plant can fill a tank and stock several more over time.
Common Problems
The most common issue is algae on the leaves, which points to too much light, too few nutrients or weak flow rather than a fault with the plant. Melting (leaves dissolving) after planting is normal as it converts to underwater growth - keep conditions stable and new growth follows.
Keep light, CO2 and fertilisation consistent, remove dying leaves promptly, and avoid burying the crown or rhizome of plants that grow from one.
Is Hornwort Right for Your Tank?
Hornwort is an easy, rewarding plant that suits almost any freshwater tank, including beginner and low-tech setups. Combine it with our other plant and aquascaping guides to build a lush, balanced planted aquarium.