Java Fern (Microsorum pteropus) Aquarium Plant Care Guide

Java Fern (Microsorum pteropus) is a true fern and a semi-aquatic plant that grows in the splash zones of streams and waterfalls. It can grow both submerged and above water. Qualities that make it a favorite for paludarium keepers. Java fern plants are great for beginner aquascapers because they need little attention besides a secure place to attach to. 

Java Fern Light Requirements

One reason Java Fern is easy to grow is because it has low lighting needs. Java Fern is found in the wild in the understory of rainforests. Light levels are low there but Java Fern gets by thanks to the density of its chlorophyll (hence the deep green color). As well as its slow growth rate.

You don’t need to provide it with high intensity plant lights. Java Fern will even grow under the standard fluorescent or LED fixtures that came with your tank. Something not many aquarium plants will tolerate. 

Java fern plants will still grow better using lights that create more photosynthetically active radiation (PAR). Under standard lights your Java Fern may maintain its size without growing much.

If you already have an established planted aquascape, don’t keep Java Fern in anything stronger than moderate lighting. In high intensity light setups the plant won’t increase its growth rate much. 

Java Fern is often stressed if exposed to strong lighting most of the time. And the slow growth rate makes it susceptible to algae in bright conditions. Algae will coat the leaves and soon kill the plant.

Java Fern Care Tips

Although this is an easy plant, Java Fern does have a few specific requirements.

Common name(s)	Java fern
Scientific name	Leptochilus (Microsorum) pteropus
Difficulty	Very Easy
Light level	Low
Growth rate	Slow
Placement	Attach to porous hard surfaces
Temperature	60-83 °F / 15-28 °C
pH	6.0-7.5

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Java Fern Natural Habitat

Wild Java fern is found in forested areas in Thailand, Malaysia, China and the Philippines. Here, it grows on riverbanks like these:

Rather than rooting in the substrate it attaches itself to rocks and other surfaces using its very strong roots. This keeps it from being swept away by the current if the river or stream it grows by swells during the rainy season.

Java fern is a rhizomatous plant, meaning its leaves and roots grow from a thick horizontal stem. Rhizomes are seen in plants that have adapted to grow outside of the soil, as is also the case with Java fern.

Java fern plants have adapted to living both under and above the water surface. That is a handy trait since the water levels of the rivers in these areas will vary with the seasons.

In our homes it means you can grow it both submersed and emersed. It’s not adapted to drying out, however, as it grows in the spray zone in the wild. Constant light misting form nearby rivers keeps the leaves moist at all times.

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Java Fern Care Requirements

You won’t need much to successfully grow Java fern in your own aquarium. In most cases it’ll thrive without much intervention on your part as long as you follow its basic care requirements.

Java Fern Light Requirements

One reason Java Fern is easy to grow is because it has low lighting needs. Java Fern is found in the wild in the understory of rainforests. Light levels are low there but Java Fern gets by thanks to the density of its chlorophyll (hence the deep green color). As well as its slow growth rate.

You don’t need to provide it with high intensity plant lights. Java Fern will even grow under the standard fluorescent or LED fixtures that came with your tank. Something not many aquarium plants will tolerate. 

Java fern plants will still grow better using lights that create more photosynthetically active radiation (PAR). Under standard lights your Java Fern may maintain its size without growing much.

If you already have an established planted aquascape, don’t keep Java Fern in anything stronger than moderate lighting. In high intensity light setups the plant won’t increase its growth rate much. 

Java Fern is often stressed if exposed to strong lighting most of the time. And the slow growth rate makes it susceptible to algae in bright conditions. Algae will coat the leaves and soon kill the plant.

Water Parameters

Java fern plants aren’t picky when it comes to water parameters so long as you avoid extremes in pH and hardness. They also grow well in cool to warm, tropical aquarium conditions.

The waters Java fern occurs in are soft and acidic and it’ll grow fastest in these conditions. They will even thrive in light brackish conditions.

Tank Size

If you want to enjoy Microsorum pteropus to the fullest it’s a good idea to grow it in an aquarium of at least 10 gallons. Not necessarily because the plant cares too much about tank size but because of its size.

It will grow tall and wide, which means it might outgrow a smaller set-up unless you prune it back. An exception to the 10 gallon rule would be Microsorum pteropus var. ‘Petite’, which was bred for its smaller size.

Does Java Fern Need Fertilizer?

Since Java Fern grows slowly it does not need much in the way of fertilizer. If you have it in a planted tank alongside other plants then it will enjoy what fertilizer you offer. But a Java Fern kept alongside fish will find plenty of nitrogen in the form of ammonia, nitrite, and nitrate from fish metabolism. 

Additional nutrients like phosphorus come in trace amounts from fish food and other sources. As a result, nutrient deficiencies are uncommon in this plant. Adding extra fertilizer for it will also be a problem unless you have other plants to feed. 

Java Fern is incapable of putting on rapid growth to take advantage of excess nutrients. If other plants aren’t around, algae will take advantage of the extra fertilizer instead.

Does Java Fern Need Carbon Dioxide?

Carbon dioxide is helpful but not required. CO2 will result in healthier, more prolific leaves, and a significant boost in growth. Java Fern is still slow growing even with CO2 but you will see an improvement.

Another reason to add carbon dioxide even to low light planted tanks is that the boost in plant growth ensures they absorb what nutrients your fish release. That makes carbon dioxide one of the best ways to keep algae at bay. Your plants are able to grow at maximum efficiency, Leaving algae with fewer nutrients to work with.

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Java Fern Aquascape

Java Fern is not easy to kill. But one of the ways aquarists do so is by trying to plant it in the substrate like you would any other plant.

Java Fern is an epiphyte and does not grow in that fashion. Epiphytes are plants that grow attached to hard surfaces. Some other examples include Anubias, another genus of popular aquarium plants, and bromeliads, an American genus of epiphytes which grow attached to tree branches.

If you root an epiphyte in the substrate, the lack of water flow, bruising, and secure surface will cause the rhizome (the black basal knot leaves grow out of) to rot. Epiphytes also don’t use their “roots” to obtain nutrients. They are used as an anchor. So rooting the plant in a rich substrate does little since epiphytes get their nutrition from their leaves. 

A new Java Fern specimen should be attached to a hard surface using glue, dental floss, or fishing line. The plant needs to be kept in place until its rhizomes penetrate and affix it in place. The process takes a few weeks, after which you can untie the plant.

When aquascaping with Java Fern, think of it as either a show specimen or a shade plant to fill in zones where other plants struggle to grow. Since it attaches to hard surfaces you attach it to driftwood and rocks to add extra greenery to these bare regions of the tank. Java Fern is a core species for Jungle Aquascapes, where we want to replicate the tangled, boggy appearance of natural environments. 

One of the nicer qualities to Java Fern is that it’s unpalatable to plant-eating fish. The leaves are very tough, fibrous, and bitter tasting. If you have fish that nibble on plants, including Tiger Barbs, Goldfish, and Clown Loaches, they will leave Java Fern alone. 

Snails, Plecostomus, and Dwarf Otocinclus also won’t eat Java Fern leaves. But they will graze algae and biofilm from the surfaces, improving the plant’s ability to photosynthesize and grow. A few dedicated vegetarians may decide to eat Java aquarium fern if there’s nothing else, like Pacus and Silver Dollars. 

Java Fern is also popular in tanks housing cichlids, which are infamous for shredding most plants. Breeding cichlids will uproot plants to make space for their eggs and fry. Others love to dig and will make pits in the gravel for their own enjoyment.

Java Fern occupies no bottom area but still provides desirable cover, so cichlids will leave the plant alone. Some larger cichlids may still try to rip out Java Fern, leaf by leaf. But the plant is bitter and tough enough to resist all but the largest and most determined cichlids.

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Propagating Java Fern

Java fern is both easy to grow and easy to propagate. There are two ways to do so: splitting the rhizome into sections or waiting for the plant to release its own babies.

Splitting the rhizome is easy to do. Cut the rhizome so that each section has at least four sizable leaves attached. And then reattach the sections to a new portion of the tank until the fern fixes itself in place. 

Make sure that you use planting scissors to cut a Java Fern rhizome because other scissors are too dull and will crush portions of the plant. These crushed sections will rot if they don’t heal, which is fatal to this slow-growing plant.

Healthy Java Ferns will also create little clones of itself nestled within the largest leaves. These plantlets will detach themselves from their parent plant once they are ready. In nature they are dispersed by the wind, water currents, or even a passing animal. 

Before they turn into plantlets the leaves will show black spots on their surface and underside. The black spots form a regular, repeating pattern so you won’t confuse them with injuries or plant disease.

These new Java fern plantlets can be collected and attached to a hard surface just like any other Java Fern. In ideal conditions you will see a few plantlets spawned every month. Allowing you to fill an aquascape with Java Fern faster than you might think for such a slow growing plant.

Placing You Java Fern in the Right Location

Due to its height, Java fern is considered a mid- or background plant depending on the size of your aquarium.

The best placement depends on the variety you’re working with. The ‘Windeløv’ variety has a more fan-shaped growth pattern than regular Java fern, making it a good mid-ground option.

Making a Java Fern Tree

All you need for a Java fern ‘tree’ is a nice piece of driftwood that imitates the branched appearance of a tree. As well as some Java fern of the right variety.

Avoid anything with long leaves like ‘Narrow’ or regular Java fern for the best effect. Instead, try going for ‘Windeløv’ or ‘Mini’. Attach the plant to the top of your driftwood and voilà, you’ve got your own Java fern tree.

Making a Java Fern Wall

If you want to make your own Java fern wall, start by making the back pane of your aquarium black using some cling film. Doing so ensures you won’t be able to see the mesh you’re using to attach the plant to.

Get your Java fern and break it up into enough little pieces to cover most of the mesh. Don’t worry if things are still looking a bit sparse at this point. The plant will fill in with time and cover all of the mesh.

Next, attach the whole thing to the back wall, making sure no clumsy fish can get behind it and hurt themselves. All you have to do now is sit back and wait for the plantlets to grow and reach their full decorative potential.

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Common Problems with Java Fern

If you’re seeing a greater amount of leaf browning than usual or if your plants’ leaves are showing yellowing or other discoloration, something might be going on.

Keep in mind that Microsorum pteropus will always feature some degree of browning on the leaves. A little browning is normal: the brown dots are the spots that plantlets can grow from. It’s not until leaves are entirely brown and come off easily that they’re dead and indicative of a possible issue.

There are two most commonly seen problems with Java fern, however:

Problem 1: Lack of Nutrients

Seeing your Java fern’s leaves develop yellow spots or melt/rot away completely?

Nutrient dosing is not necessary for this species in most cases, but sometimes there are too little to go around.

Consider dosing a liquid aquarium plant supplement. Potassium and iron are common deficiencies in aquarium plants.

Problem 2: Too Much Light

Leaf death, with leaves browning or turning transparent and coming off are a sign that your aquarium lights are scorching your Java fern.

Java fern aquarium plants grows in forested areas that don’t receive much direct sun. Meaning it’s not used to being blasted with light. Move the plant(s) to a more shaded spot in the aquarium or try turning the lights down.

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Buying Java Fern

Java fern is a popular aquarium plant and you should be able to find it in most pet- and aquarium stores. Most only carry regular Microsorum pteropus, though. So if you’d like to grow any of the selectively bred cultivars in your tank you have to turn to the Internet instead.

Java Fern Varieties and Identification

Cultivating different varieties of Java fern seems to be a popular pastime for nurseries – at least judging by the sheer number out there.

• Regular Java fern is recognizable dye to its long, ribbed, and lance-shaped green leaves. It’s the most common variety out there.
• Microsorum pteropus var. ‘Windeløv’ leaves don’t look much like the original Java fern’s at all. The variety is also called lace Java fern because the tips of the leaves have fine branches.
• Microsorum pteropus var. ‘Narrow’ features, as the name suggests, much narrower leaves than the previous two species. It can be almost grass-like in appearance.
• Microsorum pteropus var. ‘Trident’ seems to be uncommon in the hobby. It has an interesting leaf shape consisting of a thin leaf stem and then a thicker leaf that splits into very narrow ends.
• Microsorum pteropus var. ‘Petite’ is a small Java fern cultivar that looks a lot like the regular variety, just smaller. A good option if you’re worried your Java aquarium fern will outgrow your tank. Keep in mind that this one will still reach a reasonable height.
• Microsorum pteropus var. ‘Latifolia’ has broader leaves than most varieties.

Conclusion

Java fern aquarium plants are excellent for beginners that don’t want to use advanced lighting or carbon dioxide. They grow well without fertilizer so long as there are aquarium fish for nutrients. The dark green leaves are attractive and the ability of java fern to attach to hard surfaces means you can add it to any aquascape.

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