Hornwort (Ceratophyllum demersum) is one of the most versatile and hardy freshwater aquarium plants. It can be floated or anchored, grows fast, absorbs excess nutrients, and provides excellent cover for fish and fry. Best of all, it requires no CO2 or substrate—making it perfect for beginners and low-tech setups.
In this guide, you’ll learn how to care for Hornwort, whether floating or planted, along with tips on trimming, tank compatibility, and preventing mess.
Want more easy plants? See Floating Aquarium Plants for Beginners
What Is Hornwort?
Hornwort is a stem plant found in lakes, ponds, and slow-moving streams around the world. In aquariums, it’s appreciated for its feathery texture and fast nutrient absorption.
Quick Facts:
- Scientific Name: Ceratophyllum demersum
- Placement: Floating or background
- Light Requirement: Low to moderate
- CO2 Needed: No
- Growth Rate: Fast
- Temperature: 59–86°F (15–30°C)
- pH Range: 6.0–7.5
- Hardness: Soft to moderately hard water
Why Keep Hornwort?
- Excellent for floating or planted-style tanks
- Sucks up ammonia, nitrates, and excess nutrients
- Helps prevent algae outbreaks
- Great hiding place for fry and shrimp
- Doesn’t require substrate or fertilizer
- Ideal for coldwater, tropical, or breeding tanks
Floating vs. Planted Hornwort
Floating Hornwort:
- Best for fry tanks and low-tech setups
- Roots are not needed—it absorbs nutrients directly from water
- Provide shade and reduce light intensity below
- Easier to clean and remove
Anchored/Planted Hornwort:
- Use as a bushy background plant
- Can be lightly buried or tied to rocks
- May shed more if buried too deep or disturbed
- Works well in aquascaped tanks with taller plants
Lighting & Growth
Hornwort grows well in low to moderate lighting, but will thrive and stay bushier in medium light setups.
- 6–10 hours of light daily
- Avoid intense direct light—it may cause excessive growth or shedding
- Compatible with most LED and budget-friendly lighting systems
Water Parameters & Setup
| Parameter | Ideal Range |
| Temperature | 59–86°F (15–30°C) |
| pH | 6.0–7.5 |
| Hardness | 5–15 dGH |
Hornwort can handle wide water conditions, making it suitable for both tropical and coldwater aquariums.
It’s also great for:
- Outdoor tubs and ponds
- No-filter or low-tech tanks
- Fry grow-out tanks
Trimming & Maintenance
Hornwort grows fast and can get messy if not maintained.
Tips:
- Trim stems with scissors every 1–2 weeks
- Remove browning or shedding parts promptly
- Limit its spread by floating within a ring or corner
- Gently rinse under water to remove debris without damaging stems
It doesn’t root, so use suction cups, plant weights, or tie it gently if anchoring.
Tank Mates & Compatibility
Hornwort is very tank-mate friendly and safe for most setups.
Great with:
- Shrimp and snails
- Guppies, tetras, danios
- Bettas
- Corydoras
- Fry and breeding tanks
Not ideal for:
- Goldfish (they’ll tear it apart)
- Large cichlids (may uproot or shred it)
Common Problems & Solutions
Problem: Hornwort Shedding Needles
Cause: Poor water conditions, too much light, or being buried too deep
Fix: Improve water quality, float it instead, or reduce lighting duration
Problem: Algae Growing on Hornwort
Cause: High nutrients and lighting imbalance
Fix: Reduce feeding, improve flow, and trim affected parts
Problem: Plant Rotting at Base
Cause: Often due to being buried in substrate or lack of flow
Fix: Float it or tie it loosely instead of planting
Propagation
Hornwort is easy to propagate:
- Trim a healthy stem segment (4–6 inches long)
- Float or plant it in another part of the tank
- It will continue to grow and branch on its own
Read also: How to Set Up a Freshwater Planted Tank
FAQs
Can Hornwort grow without CO2?
Yes! It does not need CO2 and does very well in low-tech tanks.
Does Hornwort need fertilizer?
Not usually. It absorbs nutrients from the water column. In planted tanks, dosing liquid fertilizer may help support faster growth.
Can I grow Hornwort in gravel?
You can anchor it with weights, but don’t bury the stems—it has no roots.
Is Hornwort good for shrimp or fry tanks?
Absolutely. It offers great hiding spots and collects biofilm for shrimp to graze on.
Does Hornwort reduce algae?
Yes. It competes for nutrients and shades the water, helping prevent algae outbreaks.
Final Thoughts
Hornwort is one of the easiest, most flexible plants for any freshwater aquarium. Whether you let it float or anchor it as a background feature, it offers practical benefits like nutrient control, algae prevention, and shelter for small aquatic life.
If you’re looking for a low-maintenance plant that grows fast and works in nearly any setup, Hornwort is an ideal choice.
