Aquatic PlantsBeginner🌗 Medium light

Water Sprite

Ceratopteris thalictroides · also called Indian Fern, Water Fern, Oriental Waterfern, Sumatra Fern

🐾 Pet-safe

Generally non-toxic to cats and dogs.

A fast-growing aquatic fern with finely divided, lacy fronds that can be planted in a rosette in the substrate or left to float. An excellent beginner plant and superb nutrient exporter for combating algae.

Educational only. KinStation content is reviewed by licensed veterinarians but cannot replace an in-person exam. Always consult a licensed veterinarian or board-certified specialist for diagnosis, treatment, or any decision affecting your pet's health.

Quick facts

Category	Aquatic Plants
Family	Pteridaceae
Native origin	Pantropical (tropical regions worldwide)
Care difficulty	Beginner
Light	Medium light
Pet toxicity	Pet-safe

Light

Medium to high light gives the fastest, densest growth; tolerates lower light with leggier, more open fronds. As a vigorous grower it puts strong light to good use and helps outcompete algae.

Water

Temp 22-28 C (72-82 F), pH 6.0-7.5, soft to moderately hard water. A fast grower that draws nutrients from the water column, making it great for reducing nitrate/phosphate; respond to pale fronds with iron/micro dosing.

Soil & potting

Unlike epiphytic ferns (Java fern, Bolbitis), this fern does NOT attach to hardscape and is not grown from a buried rhizome. It can be planted in the substrate - anchor the crown/base with the rosette at the surface (do not bury the growing point), as its roots are delicate - or simply left to float, in which case it feeds entirely from the water column. Nutrient-rich substrate helps planted specimens.

Environment — humidity, temperature, placement

CO2 not required; thrives in low-tech tanks. Gentle to moderate flow. Plant in the midground/background or float it for shade and a fry/shrimp refuge. Floating specimens grow fastest and offer the best nutrient export.

Propagation

Propagates very easily via adventitious plantlets that form along the margins and tips of mature fronds; these detach, float, and root on their own. Simply pluck a plantlet and plant or float it.

Toxicity detail

Non-toxic and safe with fish, shrimp, snails, and pets; widely used as a fry/shrimp refuge. Not restricted in the aquarium trade, but it is a fast-spreading aquatic - never release into waterways and dispose of excess responsibly.

Growth stages

How this plant changes through its life — each stage often has its own care, diet and space needs.

Photo coming soon

Spore / recruit

Aquatic plants and macroalgae establish from spores, seeds, or drifting fragments that settle and attach to substrate or rock. Many freshwater aquarium plants and marine macroalgae also spread readily from a detached piece that takes root or holdfast.

Photo coming soon

Young growth

Young growth puts out its first blades, fronds, or leaves and anchors with roots or a holdfast. Submersed plants may look different from their emersed form, and growth speeds up as the plant adapts to the water's light and nutrients.

Mature

A mature aquatic plant or macroalga reaches its full size and characteristic shape, forming the dense growth, runners, or fronds typical of the species. Established plants spread to fill space and can be divided or trimmed to propagate.

Sources

Wikipedia - Ceratopteris thalictroides (encyclopedia)
Aquasabi Aquascaping Wiki - Ceratopteris thalictroides (care guide)