Ceratopteris Siliquosa / Water Sprite

Quick facts

Identity

Also known as

Indian Fern; Oriental Water Fern; Water Stag-horn Fern; Water Hornfern; Floating Fern

Synonyms

Ceratopteris cornuta; Ceratopteris siliquosa; Acrostichum thalictroides

Environment

Freshwater

Native to

Tropical Asia, Africa, Australia, Central America

Habitat

Slow-moving or stagnant fresh water including ponds, marshes, and gently flowing streams, growing emersed, floating, or fully submersed

Sourcing

Aquacultured

Conservation

Not Evaluated

Care

Care level

Easy

Growth form

Rosette

Max height

4 – 16 in (10 – 41 cm)

Spread

16 in (41 cm)

Growth rate

Fast

Placement

Midground, Background, Floating

Water

Temperature

68 – 82 °F (20 – 28 °C)

pH

6.0 – 7.5

GH

2 – 20 dGH

PAR

20 – 80 PAR

Flow

Low

Light

Medium

CO₂

Beneficial

Planting

Substrate

Any

Feeds from

Both

Fertilizer needs

Medium

Colors

Green

Feeding & breeding

Propagation

Plantlets, Rhizome division

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Care guide

Overview

Water Sprite is a fast-growing fern of the genus Ceratopteris, sold either rooted or as loose floating specimens with finely divided, bright green fronds. It grows well free-floating or lightly planted with the rhizome crown exposed, and its dense root mass shelters fry and shrimplets while stripping excess nutrients from the water column. Regular trimming keeps it from shading out lower plants.

Care

Water sprite tolerates a wide range of pH and hardness and grows either rooted in substrate or drifting free at the surface. It grows fastest under moderate to high light with some nutrient supplementation, though it survives in lower light at a slower, leggier pace. The crown of the short rhizome should stay above the substrate surface; burying it invites rot, which is why many keepers simply let the plant float instead of planting it. Regular trimming is needed since it can outcompete slower plants for light and nutrients within a few weeks.

Planting & trimming

Plant with the rhizome crown sitting just above the substrate line, never buried, or simply allow the plant to float freely at the surface where it forms a denser canopy. Trim outer fronds regularly to control size and light penetration to plants below, and remove any small plantlets that sprout along leaf margins if you want to limit spread. Floating specimens develop long, fine roots that trail into the water column and should be thinned periodically to avoid tangling with other plants or filter intakes.

Fertilizing

This fern draws nutrients from both the water column and its roots, making it an effective nitrate and phosphate sponge in newly cycling or heavily stocked tanks. Occasional liquid fertilizer or root tabs help sustain the fast growth rate, and iron supplementation keeps new fronds a deeper green rather than pale or yellowish. Yellowing or thin, stretched fronds usually signal insufficient light or a nutrient shortfall rather than disease.

Propagation

New plantlets form spontaneously along the edges and tips of mature fronds and can be separated once they develop a few small leaves and short roots. The parent rhizome can also be divided if it produces multiple crowns. Floating or emersed plants propagate especially readily, often self-seeding across the tank surface without intervention.

Problems

Low light causes pale, stretched growth and eventual melting of older fronds, so a jump to medium or higher light usually resolves the problem. Burying the rhizome crown is the most common planting mistake and leads to basal rot within weeks. Otherwise the species is largely trouble-free and rarely attracts algae once established, since it outcompetes algae for available nutrients.

Sources

1. HOW TO CARE FOR YOUR WATER SPRITE - A COMPLETE GUIDE
2. Water sprite (Ceratopteris thalictroides) - Scale & Stem
3. Water Sprite (Ceratopteris thalictroides) Care Sheet - Aquariadise
4. Water Sprite Care, Floating, Propagation and More… - Everything Fishkeeping

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