About the species

Ceratopteris thalictroides is a pantropical water fern with finely divided, light green leaves. It grows 15–30 centimetres tall and 10–20 centimetres wide, and the strongly divided leaf shape makes an airy contrast to rounder foliage. In open aquariums it happily grows out of the water and forms handsome surface leaves. Growth is fast and the plant takes up large quantities of nutrients.

Facts

• Latin name: Ceratopteris thalictroides
• Plant type: Rosette plant
• Origin: Asia
• Height: 15–30 cm
• Growth rate: Fast
• Position: Background

Light requirement

Medium light requirement. Reckon on around 0.5 W per litre or a modern mid-range LED unit. Too little light gives sparse, stretched shoots and pale leaves, while the right amount keeps the plant compact and richly coloured.

CO₂ & nutrition

Manages entirely without added CO₂, which makes it as suitable for a simple aquarium as for an aquascape. Liquid carbon or injected CO₂ speeds up growth but is never a requirement. Dose an all-round fertiliser with iron and micronutrients every week.

Planting

Plant the root ball in the substrate so the roots are covered but the crown — where the new leaves emerge — sits just above it. Burying the growth point makes the plant rot. Give it plenty of room, since the leaves spread out in a rosette.

Carefully remove the pot and rinse the rock wool off the roots before planting — leftover rock wool can otherwise hinder rooting.

Care & propagation

Cut old outer leaves off at the base once they start to look tired, and the rosette stays fresh. The plant propagates itself with daughter plants from the rootstock; separate them from the mother plant once they have their own roots and a few leaves.

Position in the aquarium

Given its mature height it belongs at the back or along the sides, where it forms a dense wall of greenery and hides equipment. In a smaller aquarium it can also be used as a solitaire in one corner.

Difficulty level

🟡 Moderate — wants stable lighting and regular fertilisation to look its best.

Delivery format

Delivered as a pot grown submerged, with the roots in rock wool. The pot holds several plants or stems that can be divided and planted separately.

Recommendation

A good plant to start a new aquarium with, since its fast growth outcompetes algae while the rest of the layout establishes itself. Small plantlets form along the leaf edges and can be broken off and grown on.