Water Sprite: Complete Care Guide

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Water Sprite is one of those plants that you can find in almost any fish shop, whether it’s a big box store or a hole-in-the-wall LFS. There’s a lot to recommend here, especially for those who are new to keeping plants. It has some uses that also make it a good plant to have around for the experienced aquascaper as well, even if it’s not part of their main display.

So, let’s dive into water sprite care headfirst, starting with some fast facts about the care of this versatile plant.

planted fish tank

Water Sprite Fast Facts

  • Common Name: Water Sprite
  • Other Common Names: Indian Fern, Oriental Waterfern, Water Hornfern
  • Scientific Name: Ceratopteris thalictroides
  • Plant Type: Floating or Planted Stem
  • Natural Habitat: Wetlands
  • Care Level: Beginner

What is Water Sprite?

Water Sprite, or Ceratopteris thalictroides, is a small-ish stem plant that’s found in marshes, stagnant water, and mangroves in the wild. There the plant roots in the mud on the bottom of the stream or floats in masses that catch on features in the water.

Water Sprite’s exact natural range is unknown, but it’s not native to the United States. It’s considered invasive in some areas, which is always a good sign for a beginner plant. Unlike some other common aquarium plants, Water Sprite hasn’t had a huge impact but it’s still non-native to the Americas.

The plant itself is actually a fern. Ferns reproduce via spores in the wild, and Water Sprite is essentially an annual in its native climate. The ferns grow and die back each year, leaving behind spores that allow them to grow quickly when conditions are right again. In private cultivation, however, the plant will survive indefinitely.

Water Sprite can grow both in the substrate and along the surface of the water. When floating it will send out roots from the various growth nodes to take nutrients directly from the water column. They’ll generally develop a bit thicker leaves if you plant them in a solid substrate.

Water Sprite prefers a lot of light, but it grows well in aquariums with low lighting. It’s a great plant for “low-tech” styles of tanks, where things are run with minimal equipment. With higher lighting and a bit of carbon dioxide, it can become a bit oppressive, growing too rapidly for most people’s tastes.

Since it’s so easy to care for, Water Sprite is a perfect plant for beginners, and it remains a versatile element of whatever aquascape it’s placed in.

What Kind of Aquarium is Right for Water Sprite?

Water Sprite will be perfectly at home in the majority of aquariums, but it does its best work in low-tech tanks and those that have a need for floating plants. It’s also an excellent choice for breeding tanks, which are often kept bare-bottomed with just a hint of plants.

It also has a little secret: Water Sprite tolerates a bit of salinity.

That makes it a great fit for brackish tanks.

On the other hand, it’s not quite as good for a more formal style of tank. It can be planted in Dutch-style rows but generally ends up looking unkempt quickly, and it doesn’t have the right profile and texture for Japanese-styled “nature aquariums.”

It remains a good choice, though not my first, for jungle tanks which take advantage of the aesthetics of overgrowth as well.

Care Overview

Taking care of Water Sprite isn’t very complicated, but if you’re new to keeping aquatic plants you may miss a couple of things. With the following in order the plant will do great!

Lights and CO₂

Low-to-moderate lighting is best for this fast-growing plant unless you don’t mind having to maintain them a couple of times per week. Carbon dioxide is unnecessary, but it will help the plant grow much more quickly.

Water Sprite seems to do well even with indirect sunlight. It may get a bit faded in those conditions, but it doesn’t require much to keep it growing. I’ve filled tanks with Water Sprite that were running a half-watt per gallon of the old-school fluorescents, light is almost never an issue.

Moderate or high lighting does result in a denser plant. If your plants look like they’re reaching, instead of forming lush growth, then upping the light will help.

Carbon dioxide is a bit much, although it’s not quite as much of a problem with a liquid source of CO₂ like SeaChem Excel. Water Sprite is marginally better about it than Anacharis, in that it won’t grow 1 ½”+ per day, but it can still accelerate the growth process too much for those who prefer less maintenance.

The bottom line is that high-tech tanks with bright lighting and carbon dioxide will support incredible growth in Water Sprite… which means more work for you.

Substrate and Fertilizers

Water Sprite seems to root best in sandy substrates, or in porous but nutritious gravels. If you’re floating the plant then it won’t make much of a difference, but for planting it you’ll want something that provides nutrients. If you don’t provide it, then you’ll have the same roots coming from growth nodes seen in floating options.

A standard broad-spectrum fertilizer will do the trick when it comes to supporting floating Water Sprite. Even that may be unnecessary, especially if you’re using it as a nutrient sink. I prefer SeaChem Flourish 

I suggest using whichever substrate appeals to you and whichever fertilizers are best for the other plants in the tank.

Maintenance and Propagation

Maintenance of Water Sprite is pretty easy: cut back what you don’t want and remove it from the tank. This applies to both floating masses and to plants that are placed in the substrate.

You may want to use a net when cutting to catch smaller, loose parts that can emerge if you’re not careful to snip only the stems. 

Propagation is also a simple task: simply plant or float the removed stems.

You can cut directly above the growth nodes to attempt to get the plant to fork, producing denser growth from a single stem. Water Sprite, in my experience, is less reliable in producing forks when cut than plants like Ludwigia sp. or Anacharis.

For those keeping it for occasional use as a nutrient sink or in a breeder tank, you can simply fill a bucket with water and drop cuttings in to grow out. Tank water is ideal since it will have the required nutrients.

The bottom line is that you’re not going to have any trouble creating more Water Sprite from a few stems.

Because of its uncanny ability to grow anywhere, you should responsibly dispose of cuttings and trimmings that you won’t use. You can dry them out and dispose of them in the trash or put them in a compost heap, just don’t put wet plants in the garbage or anywhere they can reach nearby waterways.

Use in Aquascaping

The main draw of Water Sprite is undoubtedly its versatility. Since the plant can be planted or floating and you can alter its appearance with lighting levels, you’ve got a wide range of possible looks for your plant.

And the best part is that they’ll all be just as easy to keep alive. What your Water Sprite does depends on your input, but it’s not an easy plant to kill even if you’re a complete newbie.

Floating Masses

Floating masses of stems are a popular way for Water Sprite to be used. All you need to do is float the plant by placing it in the tank, it will take care of the rest shortly.

Floating Water Sprite will have roots that come downwards into the tank after they’re established. These make a great cover for fish that are shy. It’s a good replacement for high-maintenance, low-input plants like Giant Duckweed for providing shade and cover.

One thing to keep in mind is that Water Sprite’s floating form can be quite thick when grown out. This means it will shade parts of the bottom of the tank, so be careful how much you float if you have light-hungry plants below.

On the other hand, thick mats of Water Sprite can be used in moderate-to-bright lighting to provide shade for plants that don’t do well in high lighting. Anubias sp. is a prime example. They form hard green spot algae when there’s too much light, but Water Sprite can provide enough shade to mitigate the negatives.

Floating Water Sprite can be isolated through careful use of barriers and flow. Aquarium tubing is a great choice for barriers, you can use it to “trap” the Water Sprite inside. I advise doing this away from the filter output. The falling water may push the plant downwards and allow it to escape.

Bunches or Rows

Bunches and rows are similar, but a little bit different when it comes to their use in aquascaping.

Rows are generally found in Dutch-style aquariums. These are made to mimic orderly terrestrial gardens, so the plants will be placed in carefully determined rows. Water Sprite grows well in this situation, dropping roots into the substrate and anchoring itself within a few days.

A separation of 1 ½” to 2” between plants works well. In larger tanks, you may want to create multiple rows. Stagger them so that the plants behind the first row are planted in the empty space seen from the front.

You can create movement in this way by continuing to stagger the rows in one direction or create a more orderly tank by simply staggering them back and forth.

Bunches are a bit more chaotic, and my favorite method. Water Sprite doesn’t like to fork quite as much as most plants, at least when I’ve handled it. It makes it harder to create a “bush” from only a single stem.

Instead, plant the stems with ½” to 1” between them in a circular pattern. Once these grow in it will create almost the same visual effect, and the multi-stem “bush” will just require trimming on a regular basis to maintain its appearance. 

Breeding Tank Cover

For breeding tanks, you just need a lot of stems of Water Sprite. You can simply place them in the breeding tank while it’s cycling to get them acclimated and growing.

If you need them in a hurry there’s a simple way to create a ton of Water Sprite in a week or so.

  1. Cut Water Sprite into 1”-2” sections, making sure each has at least one pair of leaves.
  2. Fill a 5-gallon bucket with tank water and put the plants in it.
  3. Add a small amount of liquid fertilizer, the recommended amount on the bottle per 5 gallons will do.
  4. Use a liquid carbon supplement daily during this process at the recommended amount per your bucket’s size.
  5. If weather permits, place the bucket outside where it will get 6-10 hours of direct sunlight per day.
  6. If weather doesn’t permit, then you’ll want to use a bright aquarium light placed over the bucket. LEDs are best for this, just make sure the light isn’t close enough to heat the water or overheat the fixture.
  7. Wait.

Within a week you should have a serious amount of Water Sprite available for your breeding tanks. They may not be pretty after this rushed growth, but they’ll be usable for cover for your fry or breeding fish depending on the project.

Maintenance is usually minimal in breeding tanks. I’ll generally just remove entire stems as the mass gets larger, but you can also trim back very large specimens and put them back in the tank.

Brackish Tanks

One of the neat things about this plant is that it tolerates brackish water quite well. It was my go-to plant for breeding Mollies for that reason, since mine were always kept in water with a bit of salt.

Using the plant in a brackish tank is the same as any other. In my experience, it does grow a little bit slower if you get your salinity over 1.010 in specific gravity. That said, it doesn’t stunt the growth in the usual sense and they still grow well in the full brackish range.

It’s something to keep in mind if you like crabs, freshwater gobies, or pufferfish. All of these will do better with plants in the tank, and Water Sprite is a solid choice.

Versatile and Hardy Water Sprite

Water Sprite may not be the most interesting plant in the world, but the lack of specialized care and its ability to survive almost anything make it an ideal beginner plant. It doesn’t stop there, however, since the plant is also versatile enough to be used in a wide array of different aquascapes. Water Sprite care is one of the best introductions I can think of for those who want to see if they have an aquatic green thumb.

So, how do you plan on using your Water Sprite?