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Hornwort (Ceratophyllum demersum)
Photo: S.Tanaka, Public domain

Hornwort

Ceratophyllum demersum

Edited by Ivan F. · Reviewed

Beginner verdict

A fast-growing, bushy plant that you can float or weigh down, and it soaks up nutrients quickly. It gives fry and shy fish lots of cover, and its growth can help hold algae back. It sheds needles when stressed, so be ready to do a little extra tidying.

Light
Low
CO2
Not Needed
Growth
Fast
Placement
Floating
Max height
12 in (30 cm)
Temperature
50–86 °F (10–30 °C)
pH
6–9
Needs substrate
No

Hornwort care mistakes to avoid

  1. Expect shedding, especially after a move. Vacuum up the fallen needles.
  2. Trim it often, because it can quickly shade out everything below it.
  3. Do not rely on it in very warm tanks, as it prefers cooler water.
  4. Keep it out of filter intakes, which needles can clog.

How it spreads

Simply break off a piece and it will grow into a new plant.

Hornwort FAQ

How tall does Hornwort grow?

Tropica lists growth to about 30 cm (12 in) in a tank, and it can grow larger over time.

What light does Hornwort need?

Tropica rates its light demand as low. Most standard aquarium lights are enough.

Should I plant hornwort or float it?

Either works. It has no true roots, so floating is easiest. Weigh it down if you would rather have it standing in the tank.

Why is hornwort shedding so much?

It often sheds when adapting to new water. Growth usually settles once it has adjusted, so scoop up needles until then.

Where to buy Hornwort

We have not found a store that sells Hornwort under its scientific name yet. We add stores as we confirm them.

Live animals and plants travel by courier. Check the store's live-arrival guarantee, and only buy once your tank has cycled (see how to cycle a fish tank).

Some US states restrict certain species. Check our US state aquarium rules table and your state's own rules before you buy.