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Ceratopteris thalictroides

Ceratopteris thalictroides

Water sprite is a fast-growing, amphibious fern forming large rosettes of finely divided, parsley-like leaves. It requires medium to high light and acts as an excellent natural filter for nitrates.

Taxonomy
Class:Liliopsida
Order:Polypodiales
Family:Pteridaceae
Genus:Ceratopteris
Species:Ceratopteris thalictroides
Formerly known as: 

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Water Temperature

18 - 30 °C

pH Value

5 - 8

Water type

Freshwater

Light

Medium to High

CO2

Low - High

Expected height

50 cm

Expected width

40 cm

KH

0 - 21 dKH

Species description

Geographical Origin and Habitat: Found throughout tropical and subtropical regions worldwide, particularly in Asia, Africa, Central and South America, and northern Australia. It populates shallow water bodies, rice paddies, wet ditches, and muddy riverbanks, displaying a prominent amphibious behavior.
Taxonomy & Genetics: Commonly known as water sprite or water fern. It belongs to the Pteridaceae family. This species shows high morphological variability based on growth conditions, a property regulated by a flexible genome that responds to light intensity and water availability.
Physical Structure: Grows forming large rosettes from which erect, widely divided, and lobed fronds extend. The roots are abundant, long, and thread-like, floating when the plant is kept adrift or anchoring in the mud. It lacks true stems, having sturdy petioles that support the leaves.
Color & Texture: Features a bright green or light olive green coloration. The visual texture is rich and deeply divided, resembling parsley or celery, creating dense and decorative bushes that break the rigid geometry of aquascapes.

Care, breeding and tankmates

Lighting & CO2: Prefers medium to high lighting. It benefits from CO2 injection in submerged setups but grows equally well without it in open aquariums if its leaves can reach the surface and access atmospheric air.
Nutrition & Substrate: Extremely nutrient-hungry. It absorbs nitrates and phosphates at an astonishing rate directly from the
Water Chemistry: Tolerates water from very soft to very hard (KH 0-21) and pH levels from 5.0 to 8.0. The optimal temperature range is between 18 and 30°C. It adapts well to stagnant water as well as moderate currents.
Space Management & Placement: Placed in the background of the aquarium to quickly fill large spaces, or left floating. As a floating plant, its roots hang down, creating a magnificent natural biotope for surface fish like labyrinth fish.
Pruning: Pruning consists of removing decayed or oversized outer fronds by cutting the petiole close to the central rosette. It must be pruned regularly to prevent it from invading the entire tank.
Risks & Diseases: Sensitive to potassium deficiency (causing pinholes in leaves) and iron deficiency (causing yellowing). The leaves are fragile and can rot if the plant is buried too deeply, covering the crown of the central rosette.

Geographic Origin and Distribution

Found throughout tropical and subtropical regions worldwide, particularly in Asia, Africa, Central and South America, and northern Australia. It populates shallow water bodies, rice paddies, wet ditches, and muddy riverbanks, displaying a prominent amphibious behavior.

Origin

South and Southeast AsiaCentral America and CaribbeanNorth AmericaAfrica and MadagascarEast AsiaAustralia, New Guinea, and Oceania

Plant profile

Placement
Midground
It is extremely versatile and can be anchored in the substrate, attached to hardscape, or allowed to float freely. Care must be taken not to bury the central rosette to avoid suffocating the plant.
Botanical form
Rosette
The plant produces deeply incised, delicate, bright green fronds that create a lush, feathery texture. As it matures, the leaves can become quite large and complex, adding significant volume to the aquascape.
Growth
VERY_FAST
It is famously fast-growing, quickly transforming from a small sprig into a massive, bushy centerpiece. Regular and sometimes aggressive trimming is required to keep its size manageable.
Substrate
Low
Ceratopteris thalictroides is an incredibly versatile fern that can be grown either rooted in an inert substrate or left to float freely at the water's surface. When planted, a simple gravel or sand base is perfectly adequate, as it primarily draws its nutrients directly from the water column through its extensive, fine root network. If planting in the substrate, ensure the crown of the plant remains slightly exposed above the gravel to prevent rotting while allowing the roots to securely anchor the buoyant foliage.
Column fertilization
Recommended
It feeds heavily from the water column, absorbing macronutrients and trace elements rapidly. Consistent liquid dosing is highly beneficial and promotes vigorous, healthy new growth.
Root fertilization
None
If planted, it establishes an extensive root system and will heavily utilize nutrients from aquasoil or root tabs. It is, however, not strictly reliant on substrate feeding.
Trimming
Occasional
To prune, simply snip off the oldest, outermost leaves as close to the base as possible. Thinning out the plant regularly ensures that light reaches the inner growth and prevents bottom leaves from dying off.
Propagation
Division
It naturally and continuously produces small plantlets along the margins of its older leaves. These baby plants can be easily detached and replanted to create a dense thicket.
Sensitivity
Moderate
It is generally a very resilient and beginner-friendly plant, though its leaves are physically delicate. It may melt slightly when first introduced to a new tank but usually recovers quickly.
Layout role
Midground, Background
It is widely used as a bright green background plant or a stunning, fast-growing centerpiece. Floating it provides fantastic cover for fry and creates beautiful, trailing roots.

Image gallery

Licensed images linked to the species or, when marked, to the closest representative taxon.

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Last updated: 06/30/2026
Ceratopteris thalictroides Care Guide & Tank Setup | Atlarium