Water Sprite – Ceratopteris species

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Overall, it is difficult to plant Water Sprite incorrectly! Whether grown with its roots in the aquarium substrate or simply left floating, this fern will generally thrive in most aquariums.

Scientific Name: Various species including Ceratopteris thalictroides, Ceratopteris pteroides, Ceratopteris cornutus and Ceratopteris richardii; Family Parkeriaceae
Synonyms: Acrostichum thalictroides, Pteris cornuta, Parkeria pteroides and others (all invalid)
Common Names: Water Sprite, Indian Fern, Sumatra Fern, Oriental Water Fern
Region: Tropical; Worldwide. C. thalictroides– tropical, worldwide; C. cornutus- mainland Africa; C. pteroides– Central and South America
Maximum Size: up to 70cm (27 inches) tall when grown submersed. Will spread to cover the entire container surface if grown as a floating plant.
pH Range and Hardness: Reportedly prefers acidic (pH 5 Р6.5), soft (DH under 10) water but I have found it to be remarkably tolerant of all but highly alkaline (pH > 8.0 water conditions).
Temperature: Tropical. Water temperatures should probably not drop below 68 degrees Fahrenheit.
Light Level: Reportedly grows best at light levels above 2.0 watts per gallon. I have had considerable success with this plant, however, at light levels of around 1.0 watts per gallon.
Ease of Growth: EASY

All species of the genus Ceratopteris are true ferns, meaning that they to not produce flowers or seeds but instead reproduce by production of spores (also commonly reproduces vegetatively). Unlike other commonly kept aquatic ferns (Java Fern, etc.), Water Sprite does not have a long-lived rhizome that attaches to the substrate and is an annual plant.

Habitat and Niche

Water Sprite may grow as a fully-aquatic or sub-aquatic (emergent) plant in its environment, which primarily includes ponds, rivers, ditches and rice paddies. It is also commonly found as a floating plant.

Appearance

The appearance of Water Sprite varies considerably depending on whether it is grown submerged or floating. There are differences between the species but, in general, Water Sprite has dark to light green leaves (fronds) that are more or less finely divided or lobed. Floating plants often have leaves that tend to be less finely divided than those grown submerged. The leaves and stems are relatively brittle and break easily.

Image
Water Sprite growing submerged with finely-divided leaves

Personal Experiences With Water Sprite
I have used Ceratopteris species in many of my aquariums over the years because of its relatively undemanding nature and rapid growth. I have found that it makes an excellent floating plant for fish that like to hide in its tangles and also as a cover plant in breeding tanks for fish that produce floating eggs, scatter eggs in plants or build bubble nests. I find that fish like Dwarf Gouramis and Blue Gouramis will frequently incorporate bits of Water Sprite in their bubble nests or will actually build their bubble nests in masses of this plant.

Although many aquarists I’ve talked to over the years have told me that Water Sprite prefers high light levels, I’ve had a lot of success growing this plant at light levels slightly below 1.0 watts per gallon.

Planting Particulars

Overall, it is difficult to plant Water Sprite incorrectly! Whether grown with its roots in the aquarium substrate or simply left floating, this fern will generally thrive in most aquariums.

Like most ferns, Ceratopteris species absorb most of their nutrients through their leaves so the type of substrate is not exceptionally important. Some authorities claim that Water Sprite will do better with the addition of some peat or clay to the substrate but I have personally found that this is not necessary for typical growth.

It is important, when planting Water Sprite in the substrate, that you do not bury the plant stem or the developing fronds.

Because of its method of gaining its nutrients through its leaves, extra fertilization is not absolutely essential for Water Sprite. In most of my tanks I simply push the plant into the substrate (or toss it on the water’s surface) and let the fish provide the nutrients it needs through their waste products. In a few tanks I provide additional fertilization in the form of Seachem’s Flourish at the normal dosing levels. I have not noticed any exceptional difference in the growth rates or health of the plants grown under these conditions.

Propagating Ceratopteris species

Like all other ferns, Water Sprite reproduces sexually by spores. This method is impractical in the aquarium. Fortunately, Ceratopteris plants also produce abundant adventitious plantlets which can be separated from the main rhizome or fronds and planted.

Other Observations

Snails and plant-eating fish will graze Water Sprite down to its roots so it is not a good selection for aquariums containing these animals. Water Sprite is also edible for humans and there was actually an experimental farm set up in the Phillipines at one time to produce Ceratopteris as a human food.

Water Sprite is such a vigorous grower that you will probably have to thin it out regularly to prevent it from taking over your aquarium. The older plants will eventually begin to turn brown and should be replaced with their offspring.

Overall, Water Sprite is a very easy and useful plant for most aquariums, as long as they do not contain animals that will eat it faster than it can grow. It enjoys high light levels but will thrive under less than ideal conditions and does not require the addition of carbon dioxide or a complex fertilization regimen to keep it growing.

References

Ines Scheurmann, 1993.
Aquarium Plants Manual – Selecting and maintaining water plants in large and small aquariums. Barron’s Educational Series, Inc.

William T. Innes, 1966.
Exotic Aquarium Fishes – 19th Edition Revised. Metaframe Corporation, New Jersey.

Holger Windelov (text by Jiri Stodola), 1987.
Windelov’s Tropica Catalog – Aquarium Plants. T.F.H. Publications, New Jersey.

Pablo Tepoot, 1998. Aquarium Plants – The Practical Guide . New Life Publications, Florida.

Hickok, L.G., T.R. Warne, and R. S. Fribourg. 1995. The biology of the fern Ceratopteris and its use as a model system. International Journal of Plant Science 156: 332-345.

Article on Water Sprite at WetWebMedia
http://www.wetwebmedia.com/PlantedTksSubWebIndex/ceratopteris.htm

Article on C-Fern
http://cfern.bio.utk.edu/resource/whatcera.html

 Last update: 2006-02-06 09:00
Author: Fruitbat
Filed under Freshwater, Plant Profiles.