Floating water sprite

Ceratopteris cornuta

Also known as Broad leaf water sprite, Indian fern, Water fern

FreshwaterFernPlantletsSpores

Floating water sprite (Ceratopteris cornuta) — Carlosar · Public domain

Care at a glance

Light: Medium light
CO2: No CO₂ needed
Temperature: 68–86°F; 20–30°C
Max height: 15.7 in; 40 cm

Growth rate: Fast
Placement: Floating
Type: Fern
pH: 5.5–8.0
Hardness: 3–18 dGH
Spread: 9.8 in (25 cm)
Nutrient uptake: Water column
Growth region: Submersed or emersed
Difficulty: Easy
Family: Pteridaceae
Origin: Tropical Africa and Asia (paleotropical)

Overview

Floating water sprite is a fast-growing fern for the surface of the tank. It is undemanding, rated easy, and suits low-tech setups.

Did you know

Floating water sprite is such an efficient nutrient sponge that fishkeepers float a clump in new or algae-prone tanks to outcompete algae. Shrimp and fry treat its dangling roots as a built-in nursery.

Caring for floating water sprite

Let floating water sprite float for the fastest growth and the most plantlets. You can also anchor the base loosely in the substrate for a taller submersed form.

It wants medium light and no CO2, and bright light keeps it compact and green instead of stringy. It feeds from the water, so a liquid fertilizer is all it needs. It handles a wide range of conditions, from 68 to 86°F (20 to 30°C) and a pH of 5.5 to 8.

It grows fast, soaks up excess nutrients and shades the tank, so plan to thin it often. Pull off the baby plantlets that sprout along the older fronds to start new plants.

Good to know

Floating water sprite is a true aquatic fern in the family Pteridaceae. Older aquarium references still use Parkeriaceae or Ceratopteridaceae for the water sprites. Its taxonomy is muddled, and many botanists treat C. cornuta as a synonym or coarse-leaved form of the widespread C. thalictroides. In the hobby, the coarser, broad-lobed plants are what get sold as cornuta. Like all ferns it can complete a full spore life cycle, but in tanks it almost always spreads by plantlets instead.

In the wild

Floating water sprite is a fern of the Old World tropics, found through tropical Africa and Asia. It grows in shallow ponds, ditches, rice paddies and slow backwaters. It either floats free, with a rosette of coarse, lobed fronds over a curtain of roots, or grows rooted in mud at the water's edge. It is adapted to warm, still, nutrient-rich shallow water.

Common questions

Does floating water sprite need to be planted in the substrate?

No. Floating water sprite floats at the surface and takes its nutrients straight from the water.

Does floating water sprite need CO2?

No. Floating water sprite grows well without added CO2.

How much light does floating water sprite need?

Floating water sprite wants medium light. A light sold for planted tanks covers it.

How do you propagate floating water sprite?

Floating water sprite propagates by plantlets. Plantlets bud from the parent and drift off.