Propagating Floating Water Sprite (Ceratopteris pteridoides)

How to propagate floating water sprite, Ceratopteris pteridoides: a fast floating fern that grows plantlets from proliferous buds on leaf margins, plus division and spores.

Overview

Ceratopteris pteridoides is a floating aquatic fern of the genus Ceratopteris, sold as water sprite. Its short fleshy rhizome roots loosely or floats freely, and its sterile fronds form broad membranous lobes. Floating at the surface, it provides dramatic shade and refuge while acting as a strong biological filter. Under bright light it grows fast and is even used to help cycle aquariums.

Propagation Method

Water sprite propagates vegetatively through proliferous buds that form in the axils and along the margins of sterile fronds. These buds develop into new plantlets that can be separated once they have their own leaves and roots. The plant can also be divided at the rhizome, and fertile fronds bear sporangia along the veins for spore reproduction.

Step-by-Step

Let a healthy floating frond mature under bright light until proliferous buds appear on its margins.
Wait for each plantlet to grow several small leaves and a few dangling roots.
Gently detach the rooted plantlet from the parent frond margin.
Float the new plantlet on the surface so its roots hang freely into the water.
Alternatively, divide an established floating clump into sections, each with leaves and roots, and float them separately.

Conditions for Healthy Growth

Temperature 22-28 C.
Bright (medium-to-high) lighting drives fast growth and plantlet formation.
Calm freshwater surface so floating fronds stay stable.
Medium nutrient demand; benefits from dissolved nutrients in the water column.
No CO2 supplementation required.

Maintenance

Thin the floating cluster every couple of weeks, removing old or yellowing fronds and harvesting surplus plantlets so light still reaches the tank below. Detaching plantlets promptly keeps the parent fronds vigorous and prevents a single mass from shading the whole surface.