Java Fern (Microsorum pteropus)

Choose Java fern for easy, long-lived green

Java fern (Microsorum pteropus) is a water fern from tropical Asia and one of the easiest plants you can keep. It grows from a creeping rhizome that grips wood and stone with fine roots, so it does not need planting in the substrate at all. Tropica rates it easy: it grows slowly, has a low demand for light and CO2, reaches 15–30 cm and is described as a hardy plant that grows in all conditions.

In the wild it grows attached to roots and rocks along riverbanks, fully or partly under water, as long as its roots and rhizome stay wet. Wikipedia gives its range as mainly Malaysia, Thailand, north-eastern India and parts of southern China, while Flowgrow describes it as widespread in tropical and subtropical Asia, from India and southern Japan to New Guinea.

The name has changed more than once. Botanists now often place it in the genus Leptochilus as Leptochilus pteropus, the name Wikipedia uses, while Tropica, Flowgrow and the aquarium trade keep Microsorum pteropus; older names include Polypodium pteropus and Colysis pteropus. It belongs to the fern family Polypodiaceae. Several cultivars exist, including 'Narrow', 'Needle Leaf', 'Windeløv' and 'Trident'; this listing is the standard form.

Decide from the complete growing picture

Because it lives on hardscape rather than in the substrate, Java fern solves a common problem: fish that dig cannot uproot it. Our fish for planted aquariums collection lists peaceful species that suit a planted set-up.

Select a bunch or a potted plant

Each purchase is one bunch or one potted plant, chosen with the Format option. Plant size and the number of leaves vary with the growing season, so the photograph shows the species, not the exact plant you will receive.

Prepare each format the right way

• Bunch: rhizomes with leaves and roots attached. Rinse them, and separate any pieces that come apart naturally rather than cutting healthy rhizome.
• Potted: take the plant out of the pot and gently remove the growing material from the roots before you attach it to wood or stone.
• Either format: look the plant over for snails, eggs or other small hitchhikers, and trim off any damaged leaves.

Plan the hardscape first. Java fern grows slowly, so it is worth deciding exactly where each plant will sit before it arrives: moving it later means untying it from the décor.

Dispatch days and arrival times are on our delivery information page.

Plan space for a slow, broad plant

Tropica gives a height of 15–30 cm or more. Flowgrow does not give one figure, noting that size varies widely between forms, and places it as an epiphyte in the midground or background, especially on driftwood. It also says it can be fixed to the glass with suction cups or left floating.

Slow growth means each leaf lives a long time and the plant keeps its shape for months. It also means a small plant stays small for a while, so choose a spot where its final spread will not crowd the swimming area.

Use a three-step space check

1. Pick the anchor: a piece of bogwood or a stone in the midground or background, where the rhizome can sit above the substrate.
2. Allow the height: leave 15–30 cm of water above the rhizome for the standard form to reach its full size.
3. Keep the front open: the long leaves arch outwards, so set the plant back from the open swimming area.

For a tank with lots of bogwood, Java fern pairs naturally with fish that like wood, such as the Bristlenose Pleco; our bristlenose pleco care guide explains why wood matters to them.

Keep light low to moderate and CO2 optional

Tropica rates both its light and CO2 demand as low. Flowgrow says it grows in low to high light, that moderate light is enough, and that it does not require added fertiliser or CO2. Wikipedia adds that it can grow in tap water, in dim or bright light, and with or without gravel.

Match light, CO2 and nutrients to the plant

Because each leaf lives so long, any algae that settles on it stays visible, and slow-growing leaves collect algae most readily under very bright light. Keep the lighting period moderate. Our algae control guide explains how to balance light and nutrients.

Tied to wood or stone, the plant has no roots in the substrate and feeds from the water, so if you fertilise, use a liquid fertiliser rather than root tablets, and choose a shrimp-safe one if you keep shrimp.

Keep water within its range

Flowgrow gives a tolerance of 4–30°C, a best range of 20–28°C, pH 5–8 and carbonate hardness 0–14 °dKH. Tropica and Wikipedia give no water values, and Wikipedia simply notes that it grows in tap water. In practice that means a normal tropical aquarium and most UK tap water.

Separate the plant's range from your fish's range

The wide tolerance means Java fern also survives in cooler indoor aquariums, below its best range, where it grows more slowly. Your fish set the final targets; compare your tap water and aquarium readings with them using our water matcher.

Attach the rhizome, never bury it

The rhizome is the horizontal stem that the leaves and roots grow from, and it must stay uncovered. Tropica says to attach the plant to a root or stone with fishing line until it has gained a hold, and warns that if it is planted in the substrate, the rhizome must not be covered because it will rot. Flowgrow agrees: only the roots should go into the substrate, and the plant can also be held down with pins or stones. Wikipedia notes that it is usually tied or glued on by its rhizome.

Use a first-week checkpoint plan

Tie firmly but not tightly. A tie that cuts into the rhizome damages it; a tie that is too loose lets the plant drift. Check it during each water change until the roots have taken hold.

Propagate from the rhizome and the plantlets

Java fern multiplies in two ways. Tropica says it is easy to propagate by splitting the horizontal rhizome, and Flowgrow adds that you can cut it with sharp scissors or a knife, or break it apart. Older leaves also grow small daughter plants: Wikipedia notes that they form on the leaf tips and margins and can float away to a new spot if the parent leaf comes off, and Flowgrow says they appear on the undersides and tips, and less often on the roots.

Make each division count

1. Choose a long rhizome with plenty of leaves.
2. Cut it into pieces that each carry several healthy leaves and some roots.
3. Attach each piece to its own wood or stone, rhizome uncovered.
4. Leave plantlets on the parent leaf until they have a few roots of their own, then pick them off and attach them.
5. Collect any leaf that comes loose; its plantlets can root wherever it settles.

Flowgrow notes that cutting off daughter plants or bending the midrib of a leaf can encourage more to form. Divisions grow slowly at first, just like the parent plant.

Tell harmless spots from real problems

Two very different things show up as dark marks on Java fern. Tropica explains that the spots under mature leaves are sporangia, reproductive organs, and not signs of disease as many believe. They are neat dots in rows or clusters on the underside. Flowgrow, on the other hand, notes that blackish-brown spots often appear on the leaves themselves, and that a good nutrient supply, CO2 and water movement help prevent them. Those patches spread and spoil the leaf.

Pair each sign with an action

Change one thing at a time and judge the result by new leaves, because damaged old leaves do not recover.

Choose tank mates that let it settle

Java fern suits a wide range of tropical communities. Because it is fixed to hardscape, fish that dig in the substrate cannot uproot it, which makes it a good choice for small cichlids such as the Kribensis Cichlid (see our Kribensis guide). Wikipedia notes that it is more resistant to snails than many plants and does better with higher fish loads.

It also suits calm planted communities, such as the Honey Gourami, and its leaves give Amano Shrimp a surface to graze. Use our tank mates tool to check that the fish you have in mind suit each other as well as the plant.

Screen companions with four questions

1. Do the temperatures overlap? Keep the aquarium within the fern's 20–28°C best range and each fish's own range.
2. Does the fish eat plants? OATA warns that goldfish can readily eat live plants, so watch closely at first.
3. Does the fish dig? Diggers are fine, as long as the fern is tied to wood or stone rather than planted.
4. Is there enough wood or rock? The fern needs a surface to grip, and so do many of the fish that suit it.

Keep it in the aquarium

Java fern is an aquarium plant. Flowgrow notes that it also grows above water in humid terrariums and paludariums as long as the substrate stays moist, which is an indoor use. OATA, the UK ornamental aquatic trade association, advises that aquarium plants should never be used in ponds because of their potential to become invasive.

Dispose of leaves and plantlets safely

• Never rinse plants, old leaves, plantlets or aquarium water into a sink, drain, pond, stream or river.
• Let unwanted leaves and plantlets dry out, then put them in household waste or compost them well away from water.
• Follow the Be Plant Wise message that OATA supports: know what you grow, stop the spread, and compost with care.

Our live plants for beginners guide covers Java fern alongside other easy plants for wood and stone.

Answer Java fern buying questions

Do I plant Java fern in the gravel?

No. Attach it to wood or rock. If you do push it into the substrate, put only the roots in and keep the rhizome above the surface so it does not rot.

What are the dark spots under the leaves?

Neat rows or clusters of brown dots under mature leaves are sporangia, the fern's spore-bearing structures. Tropica points out that they are not a sign of disease. Black or brown patches that spread across the leaf are a different problem, usually linked to nutrients or poor water movement.

Does Java fern need CO2?

No. Tropica rates both its light and its CO2 demand as low, and Flowgrow says it needs no added fertiliser or CO2, although both help.

How big does Java fern grow?

Tropica gives 15–30 cm or more for the standard form. Flowgrow notes that size varies widely between forms, and narrow-leaved forms stay smaller. It grows slowly, so it reaches its full size over months.

What temperature does Java fern need?

Flowgrow gives a best range of 20–28°C and a tolerance of 4–30°C, with pH 5–8 and carbonate hardness 0–14 °dKH. A normal tropical aquarium suits it.

How do I propagate Java fern?

Cut or break the creeping rhizome into pieces that each carry several leaves, or pick off the small plantlets that grow on older leaves once they have roots of their own, and attach them somewhere new.

Why are my Java fern leaves turning black?

Spreading black or brown patches usually point to a shortage of nutrients or poor water movement; Flowgrow says a good nutrient supply, CO2 and water movement help prevent them. A rotting rhizome, usually from being buried, also blackens the leaves. Remove badly affected leaves and fix the cause.

Will my fish eat Java fern?

Its leaves are tough, and Wikipedia notes it is more resistant to snails than many plants. Even so, OATA warns that goldfish can readily eat live plants, so watch any plant-eating fish when you first add it.

Consult the plant references

• Tropica: Microsorum pteropus — difficulty, slow growth, low light and CO2 demand, 15–30 cm height, attaching to roots and stones, never covering the rhizome, splitting the rhizome, and sporangia under the leaves.
• Flowgrow plant database: Microsorum pteropus — light and CO2 ranges, temperature, pH, KH, nutrients, placement, propagation from rhizome and plantlets, emersed growth, the trade name history and the advice on blackish-brown leaf spots.
• Wikipedia: Leptochilus pteropus (Java fern) — family, native range and habitat, cultivars, the accepted name Leptochilus pteropus, attaching by tying or gluing, tolerance of tap water and light, and plantlets on the leaves.
• OATA: Aquatic plants and Be Plant Wise — UK trade guidance that aquarium plants should not be used in ponds, the Be Plant Wise campaign and safe disposal.
• OATA: How to look after goldfish in an aquarium — the warning that goldfish can readily eat live plants.
• Tropical Fish Co delivery page — current dispatch days and arrival times.