Water Sprite (Ceratopteris thalictroides) Care Sheet

Jennifer Doll

Jennifer Doll


Water Sprite

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Water sprite is one of the easier freshwater plant species you can get for your aquarium. This plant can either be planted in the substrate or floated at the surface of the water to provide shelter and shade for fish below. Water sprite is also an incredibly fast grower and will need to be trimmed often. In addition, if you’re trying to breed fish or invertebrates, these clippings make for perfect spawning areas.

Keep reading to find out everything you need to know about water sprite plant care and keeping this freshwater species in your own aquarium!

Water Sprite Care Guide


Ceratopteris thalictroides is commonly known as water sprite, water fern, oriental water fern, Indian water fern, and water horn fern. The water sprite plant is actually considered a fern and is placed in the Ceratopteris genus which is designated to exclusively aquatic homosporous ferns.

Species from this genus are commonly used as model organisms in genomic studies due to their fast growth rate and easily observable phenotypes. As of July 2020, less than 10 different species have been documented.

What are water sprites?

In European mythology, water sprites are synonymous with water fairies who are able to breathe both air and water; they are sometimes portrayed as being able to fly as well. They are considered a type of diety more than a mythical animal and have been portrayed in many different ways across countries and cultures.

It is possible that Ceratopteris thalictroides was given its common name after these mystical creatures due to its ability to be grown submersed and partially emersed!

Natural habitat

Water sprite has a very natural wide range and can be found growing in most tropical locations on almost every continent. They can survive most water conditions but tend to do best in slow-moving or standstill waters like ponds and swamps. Water sprites can be seen growing from the substrate or as a floating plant. They also do well in both shady and sunny areas.

Water sprites are annuals. This means that they will need to drop their seeds in order to come back the next year; this is in contrast to perennials, which will regrow themselves the next year from remaining root systems.

Because of its fast growth rate and adaptability, the water sprite plant has become an invasive species in many tropical states and countries. Since it can grow in a wide range of conditions, it can easily overtake and outcompete other endemic plant species that are crucial for the health of the local ecosystem.

Is water sprite edible?

Apart from being a model organism for genomic studies, water sprite is a common dish in some parts of the world, including Madagascar, Vietnam, and New Guinea. However, it is possible that the plant contains carcinogens even when cooked, so caution should be taken if planning to harvest. Remember, never eat anything that comes out of your fish tank!

In some parts of New Guinea, the water sprite plant is sometimes even used as personal decoration.


Telling plants apart can be difficult, but there are a few ways to confidently identify water sprite. Water sprite is usually bright green and stands tall in the aquarium when planted in the substrate. These plants have a central stem with delicate leaves that extend out from various locations on that stem. If left to float, the plant will tend to become entangled with itself and the roots will grow down towards the bottom of the tank.

Water sprite can grow to a foot (30.5 cm) or more, and can potentially start to partially grow above the surface of the water.

Water Sprite

Water sprite tank requirements

Water sprite is one of the most forgiving aquatic plants and doesn’t take too much to keep it happy. However, make sure to be prepared to have to keep up with trimming and pruning if you don’t want this plant to take over your aquarium!

As these plants are found in slow-moving waters, they will not do well in an aquarium with high flow and should never be placed in a direct water current; this is especially important if you’re planning to keep your water sprite plant floating.

Interestingly, these plants are naturally found at moderate water depths despite their affinity for high-intensity lighting. In the aquarium, this means that they can be placed practically anywhere, though placing them at the back will temporarily keep from taking away from valuable swimming space towards the front. It is recommended to keep these plants under moderate lighting to help control growth rate, but high-intensity lighting can also be used if willing to provide additional maintenance and upkeep of growth.

Note: It should also be warned that keeping an aquarium with high lighting will most often times result in a constant battle between maintenance and algae growth. Water sprite is a good option for exporting nutrients and ultimately helping starve algae before it can take root.

Water conditions

Water sprite is naturally found in areas with less-than-ideal water conditions; more important than getting the ‘right conditions’ is getting stable conditions in your aquarium.

To keep healthy and happy water sprite, water temperature should always be constant between 68-82° F (20.0-27.8° C) with pH between 6.5-7.5. One thing to consider when stocking your planted aquarium though is that water sprite seems to prefer softer water, with KH between 3-8.

A popular use for water sprite is as a nutrient export; all plants, including aquatic plants, uptake certain nutrients in order to grow and stay healthy. Because water sprite tends to grow so fast, that also means that it requires a lot of nutrients to do so. Some hobbyists with excess nutrient problems have turned to water sprite to help organically remove nutrients from the water in their aquarium.

While this is a temporary fix to a nutrient problem, it cannot be sustained if the influx of nutrients does not last. The plant will either need to be transplanted or nutrients will eventually need to be supplemented into the aquarium system.

Is water sprite a low light plant?

Though a very easy beginner plant, water sprite will not do its best under low lighting. This plant thrives in moderate to high lighting. Low light may cause the plant to stretch for additional light and/or lose its vibrant green coloring.

While floating water sprite under low light might bring the plant closer to the light source, it will probably still not be enough for the plant to grow at its fastest and healthiest rate.

For a full list of low light plants, make sure to check out our guide on the 9 most useful low light aquarium plants here.

Water Sprite Care Guide

Water sprite tank mates

Fish and invertebrates will love water sprite. As a substrate plant, water sprite offers a dense coverage and makes for a safe retreat for the inhabitants in your aquarium. Floating water sprite not only offers safety for upper water column swimmers, but it also shades fish, invertebrates, and other plants below.

Water sprite is an especially popular floating plant used for raising fry; it will grow just in time for when eggs hatch and then offer a safe haven for young fish and invertebrates to grow. However, it is important to remember that these plants grow their best when put under high lighting; most fry can’t tolerate overly intense lighting so water sprite might not be the best plant option until the fish or invertebrates have grown a decent amount.

Otherwise, water sprite can either be planted or kept as a floating plant in the community aquarium. Fish that are prone to uprooting or eating plants, like cichlids and goldfish, should be avoided as your water sprite will quickly disappear in one way or another! Water sprite always tends to be a favorite plant-snack for snails, so keep an eye on if leaves start becoming less abundant and/or your snails are hanging out on the leaves a little too often than you would like.

As for plant tank mates for water sprite, some special consideration needs to be given. These are moderate to high light demanding plants while the majority of freshwater aquarium plants are on the lower end of lighting needs. This means that while water sprite will thrive under the right conditions, other plants may not be able to adapt to higher light intensities and melt away. Some compatible moderate- to high-lighting plants are:

  • Dwarf baby tears (Hemianthus callitrichoides)
  • Dwarf Sagittaria (Sagittaria subulata)
  • Red tiger lotus (Nymphaea zenkeri); needs slight caution/acclimation when being planted under higher lighting.
  • Christmas moss (Vesicularia montagnei); also needs slight caution/acclimation under higher lighting, but will do well when planted under floating water sprite.

At the same time, it is possible to keep floating water sprite in a low-tech aquarium with low lightning since the plant is that much closer to the source. However, even under low light, these plants still tend to grow fast and can quickly overtake the upper water column. This will mean that any plants below can potentially be cut off from a steady source of light unless the water sprite is regularly maintained.

For other plant species that can be grown towards the back of your tank with your water sprite, make sure to check out our guide on 7 beautiful background aquarium plants here.

Methods for planting water sprite

So what is the best way to plant your water sprite: in the substrate or left as free to float? It is important to consider the effect that you want your water sprite plant to have in your aquarium. There is also some controversy about which method is the most effective when it comes to exporting nutrients.

Floating water sprite

Floating water sprite will add color to the top of your aquarium, provide shade for plants and fish below, and act as a natural refuge for upper water column swimmers. Even more so, there is some argument that floating water sprite does a better job of exporting nutrients than planted water sprite.

Since the roots will grow directly into the water column, water will flow directly around and in between the root filaments, hypothetically leading to more nutrients being uptaken from the water. Simply place a piece of water sprout plant at the surface of your aquarium and watch as it quickly grows and expands!

Water Sprite

Planted water sprite

Planted water sprite can create a beautifully dense and bushy backdrop for the community aquarium, and will grow towards the light; fish and invertebrates will love to dart in between the stems and leaves. However, the other side of the argument seems to say that by planting water sprite in the substrate, you are causing the roots to uptake what is available in the substrate as opposed to what is available in the water column.

Some hobbyists have seemed to come to an agreement on a certain method of planting water sprite in substrate so that it is also efficient at exporting nutrients from the water column. The trick is to keep the upper root system out of the substrate so that some parts of the root are still exposed to the water. This has resulted in similar exportation rates to the floating method but keeps the water sprite growing strong towards the light while securely in place.

Propagating your water sprite plant

Water sprite will grow rapidly on its own, but if you want to plant it somewhere else in your tank or want to give a piece away to another hobbyist, you will need to know how to safely propagate the plant. Water sprite can grow plantlets and can also grow adventitious roots; this makes propagation incredibly easy but can also quickly lead to overcrowding.

For propagation via plantlets, the main plant will start to grow tiny plantlets that will grow on the leaves or stems. These plantlets will then detach from the plant and become their own independent plants with individual root systems. These plantlets can be collected and replanted where desired; this ability can quickly lead to overcrowding so it is good to be aware of when your water sprite has grown plantlets.

Another way to propagate water sprite is by purposely cutting a portion of the plant and replanting it. This portion will grow adventitious roots, meaning that the plant is able to regrow its own root system after being injured and/or severed from the main plant.


Water sprite is a beautiful, easy, and fast-growing freshwater plant that can fill up the backdrop or upper water column of your tank. It is excellent at exporting nutrients from your system, but can quickly overgrow other plants and obstruct flow. These plants thrive under high lighting, so take care when choosing other plants and make sure that they can tolerate high intensities as well. Otherwise, this plant will surely provide a natural environment for your fish and invertebrates to display their best behaviors!

If you have any questions about water sprite care or have kept one of these plants in your own aquarium, don’t hesitate to leave a comment below!

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