Java Fern (Microsorum Pteropus) is one of the most versatile plants in the aquarium hobby and the most forgiving when it comes to beginner’s mistakes. Among our customers and certainly ourselves at Castle Dawn Aquatics it is one of the most commonly used plants in blackwater biotopes due to its love of low light and its remarkable adaptability to acidic water. The plant's versatility knows no limits but it does not mean it is indestructible and will quickly tell you when it's not happy (See common problems).

Origin Story

Java fern belongs to the Polypodiaceae family which consists of 56 genera and around 1,200 different species, with the Java fern (Microsorum pteropus) being one of the most well-known species in the Microsorum genus within the aquarium trade.

Native to Southeast Asia, Java fern can be found throughout the Jungle growing almost anywhere in and out of water. On our fish collecting trips to Malaysia, we would often see it growing in the most unlikely places, attached to stones, trees, and even old animal bones. Java fern can succeed in any condition making it an ideal plant for beginners.

Since the Java fern (Microsorum pteropus) was introduced into the hobby back in the early 1970’s multiple variants have turned up in the market with the most common being:

Microsorum Pteropus TRUE Needle Leaf Java Fern

The Microsorum Pteropus Needle Leaf Java Fern is renowned for its complex foliage of narrow vibrant green leaves. TRUE needle leaf Java fern is very rarely seen in the aquatic trade and in turn demands a high price. However, it is not as tolerant as the other variants and does not fair well in low pH. This species is commonly mislabelled as Microsorum brassii.

Microsorum Pteropus Narrow Leaf Java Fern

Microsorum Pteropus narrow-leaf Java fern has slender, delicate leaves and is one of the more popular varieties of Java fern in the aquatic trade. Narrow-leaf Java fern is the tallest of the Microsorum Pteropus variants and can reach up to 15 inches in height, making it an ideal background plant for an aquarium aquascape.

Microsorum Pteropus Trident Java Fern

Another rare species in the hobby although common in the wild, we would often see it during fish collecting trips in Borneo. Its leaves are long and narrow forking as it matures. Trident Java fern is one of the more prolific growing variants and quickly can become a central focal point in an aquascape design.

Microsorum Pteropus Windelov Java Fern

Last but not least the old faithful Windelov Java Fern, when most aquarists think of Java fern this is the plant that pops into their heads. It is the most versatile out of all the Java fern variants and will happily endure the most extreme aquarium conditions. It can easily be identified by its divided leaf tips and bushy appearance.

Microsorum Pteropus Java Fern Care

While Java ferns (Microsorum Pteropus) are mostly self-sufficient, they do need some attention to remain healthy. Otherwise, your Java fern could succumb to common ailments associated with the species. Unlike similar aquarium plants, Java ferns do not need additional CO2 equipment to prosper making them ideal for low maintenance aquariums.

Water Parameters:

Java fern will be content in hard or soft water. In the wild Java ferns are more commonly found in and around soft water areas with a pH as low as 3.9. However, its growth becomes stunted when the pH value is lower than 4.0 and will not propagate as prolifically.

In a standard aquarium keep the Java fern in water with a pH between 5.5 and 7.0 with a hardness of  0 - 30°dGH, this will ensure lush green leaves and steady growth. 

Temperature:

Temperature is another forgiving aquarium parameter in regards to the Java ferns needs. Java fern is comfortable in temperatures between 18 °C to 28 °C, and won't be bothered if the temperature swings a few degrees either way.

Lighting: 

Java ferns do not require a lot of light another reason why they are commonly used in blackwater biotopes, is tannins can limit light transmission which in turn can make life difficult for most aquarium plants whereas Java ferns flourish.

It is also worth noting that too much light can be detrimental to Java fern and can cause damage to the plant over time. Java ferns live deep within humid forests shrouded from light, so most standard aquarium lights between 4500k – 7000k will be more than sufficient to keep the Java fern happy.

Substrate:

Java fern does NOT do well in aquarium substrate making it ideal for bare bottom aquariums. Java fern prefers to be attached to a piece of hardscape such as rock or driftwood.

The reasoning behind this is that Java ferns rhizomes need to be exposed as they absorb nutrients from the water. Burying rhizomes deep within the aquarium substrate can actually stunt the plant's growth and over time lead to issues such as Java fern melt. 

Java ferns rhizomes. Buried rhizomes can stunt the plants growth.

PRO TIP: If you purchase your Java fern in a wrap or pot, remove it to ensure optimum growth. If it is essential to put the Java fern in the substrate, tie it to flat lava rock keeping the Java fern just above the surface of the substrate.

Common Problems

Java fern melt

These innocent brown patches can quickly spread throughout the leaf deteriorating the whole plant if left unchecked.

If you notice brown or black patches starting on the inner part of the leaves of the Java fern the plant may be suffering from Java fern melt.

These patches tend to spread, deteriorating and melting the leaves eventually killing the plant. Most aquarists when they see these patches consider the Java fern as good as dead.

Although, from personal experience, it is a sign the plant is lacking potassium. Instead, of giving up on the Java fern, remove the infected leaves and increase potassium levels in your plant feeding routine, this should perk the Java fern up and prevent any further spread.

Black or Brown Spots under Leaves

Sporangia spots are often mistaken for deteriorating patches (Java Fern Melt), these spore spots are one of the many ways Java ferns reproduce.

Not to be mistaken with deteriorating patches, we often get customers asking what is wrong with their Java fern as spots have appeared under the leaves. These spots are called sporangia and nothing is wrong with the Java fern, it simply means the plant has reached maturity. From these sporangia spots, new Java ferns will sprout.

Leaves Turning Translucent

A common problem with plants that have a dislike for strong light, the leaves start to go translucent. It is the plants' way of telling you to tone it down a little or put me in the shade. 

A common problem with Java fern is the result of too much light. The Java ferns native environment is shaded by forest growth or in water that is tannin-rich which limits the light spectrum.

Java fern is very easy-going in its care, but when it comes to light they appreciate a little bit more attention. If you use intense lighting on your aquarium the Java fern will be happier situated in sheltered areas.

Foliage Maintenance

Java fern is mostly slow-growing and can be left to its own devices without becoming unmanageable unlike species such as Cabomba. As they are not rooted plants they will grow steadily with or without a regular feeding regime. That being said liquid fertilizers will boost growth and can help prevent the dreaded Java fern melt discussed in common problems.

Due to its slow growth rate, you should only need to give your Java fern a prune a couple of times a year. However, mature plants can get untidy with plantlet growth. Depending on the desired aesthetic of your aquarium, you may wish to prune parent leaves that are heavy with plantlets on a regular basis.

PRO TIP: When the Java fern begins producing plantlets, liquid fertilizers rich in potassium, manganese and iron will help prevent the parent leave from rot.

Propagation (Breeding)

To propagate Java fern simply cut down through the rhizome with sterile aquarium scissors and divide into as many sections as you require. The sections can be tied to driftwood or stone with aquascaping thread till the rhizome take hold or use aquatic safe glue.

Another way is to wait till your plant is mature and starts producing plantlets. The plantlets can be cut with aquarium scissors and attached to aquatic mesh frames or plant disks till they have matured enough to be attached to a larger aquatic hardscape.

PRO TIP: Some aquarists use glue to attach Java fern plantlets but this can smother the small delicate rhizome which can stunt growth or even kill them. Use aquascaping thread or plant straight into aquatic plant fertilizer disks. This will allow the small plants to grow unhindered.

Aquarium Myths

Is Java fern right for you?

Java Fern Microsorum Pteropus Is The Most Forgiving Plant in The Aquarium.

Java fern is right for any aquarist from beginner to expert, it is a humble aquarium plant that doesn’t ask for much and gives a lot in return. It will put up with most beginners mistakes and will handle any aquarium parameters. Each variant of Java fern is unique and will bring its own aesthetic to the aquarium and I am confident it will become a favourite of yours and your fish.   

We hope you enjoyed and found this article useful. If you have any further questions about Java Fern (Microsorum Pteropus) care please leave them in the comment section and we will get back to you.

The article was written based on personal knowledge and experience in keeping the species. It may differ from your own experience or opinions of the species.

Disclaimer: All images are credited accordingly, if an image is miscredited please contact us at blog@castledawnaquatics.com