Water sprite (Ceratopteris thalictroides) is an easy to cultivate, fast growing beginner plant that is the suitable for a wide array of aquariums and water types. It can be found on nearly every continent and has an extremely wide distribution. It is currently established in Central America, South American, Asia, Africa and Australia.
It grows in a wide range of habitats, and in the wild it grows in swamps, flooded forests, marshes, ponds, and many other bodies of water with slow or stagnant water. It generally only survives for a year in the wild, but will live almost indefinitely in a home aquarium.
Water sprite will grow like a weed under the right conditions, and thankfully the right conditions are easy to achieve. All that you have to provide is the proper lighting and nutrients and it will thrive in an aquarium. In fact, it grows so quickly that it can completely overrun an aquarium, and will even begin to extend shoots out of the water, which gives it a unique look in an uncovered aquarium.
While it grows best planted in the substrate, water sprite can also grow as a floating plant. Numerous offshoots will often break off the mother plant and create floating plants, which will grow into dense floating mats, and create a perfect refuge for newborn fry.
Water sprite does best under to medium to high light conditions, but will still grow under low light conditions – albeit at a much slower rate. It’s always best to use a full spectrum light and algae growth is usually not a concern in a tank with water sprite. Its fast growth and nutrient consumption allows it to directly compete with algae, and at the very least, it will slow any algae growth in the tank.
Like most plants, it appreciates the addition of CO2, but it will still grow quickly without any additionally CO2. Trace elements should be added though, and if your water lacks certain nutrients, growth will be significant slowed. When adding trace elements, I always use Seachem Flourish Trace Elements 500ml available at Amazon.com.
Water sprite reproduces the same way that all ferns do, and adventitious plantlets form on the parent plant, which are then released into the water. Because of this, you will notice numerous floating plants in an aquarium, which will then grow into full plants.
You can hasten reproduction by breaking off leaf tips and allowing them to float in the water column or by planting them directly in the substrate. These will grow into full plants in a short period of time.
Water sprite is compatible with most species of fish, although many of the larger species tend to graze on the fine leaves of the plant. As with many plants, goldfish and larger cichlids will quickly reduce this plant to a stub, though cichlids do tend to ignore it when it’s used as a floating plant.
One of the greatest dangers to water sprite is snails, and they will quickly destroy any water sprite that they share an aquarium with. There is some anecdotal evidence that Malaysian trumpet snails are safe with water sprite, but that has not been confirmed at this point.