Category: Plants

The Amazon sword is the classic large background plant for a planted aquarium. It grows tall, broad leaves from a central rosette, tolerates medium light with no added CO2, and is easy to keep. The one thing it genuinely demands is a well-fed substrate, because it feeds through its roots.

Feed it through the roots

Echinodorus grisebachii is a heavy root feeder. Liquid fertiliser in the water column does comparatively little for it, so the nutrients need to be where its roots are.

Use root tabs pushed into the substrate near the plant, or grow it in a nutrient aquasoil that supplies them directly. An Amazon sword in plain inert gravel with no root feeding will survive and stay small and pale, which is usually what people mean when they say theirs is not doing anything.

Give it room

Requirement	Amazon sword
Light	Medium
CO2	Not required
Difficulty	Easy
Growth rate	Medium
Placement	Rosette, background

This is a big plant. Put it at the back, give it space, and expect it to shade whatever sits behind or beneath it once it fills out. In a small tank a mature sword can dominate the whole layout, which is fine if that is the intention and a problem if it is not.

Its size and loose habit make it a natural fit for the jungle style, where overgrowth is the point, and for a South American biotope, since it belongs to that region.

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Amazon sword questions

Do Amazon swords need root tabs?

In inert gravel or sand, yes. It is a heavy root feeder, so it needs nutrients at the roots. In a nutrient aquasoil the substrate already supplies them.

Does an Amazon sword need CO2?

No. It grows well in medium light without added CO2. Root feeding matters far more to this plant than carbon does.

How big does an Amazon sword get?

Large enough to be a background plant in most tanks and to overwhelm a small one. Plan its position on the assumption it will fill the space rather than on the size of the pot you bought.

Anubias is the plant to start with if you have killed everything else. It grows in low light, needs no added CO2, attaches to wood and rock instead of rooting in substrate, and tolerates a level of neglect that would finish most aquarium plants. The trade-off is that it grows slowly.

What it is

Anubias is an epiphyte, meaning it grows attached to surfaces rather than planted in the substrate. Thick, dark, leathery leaves rise from a horizontal stem called a rhizome. The most common variety in the hobby is Anubias nana, Anubias barteri var. nana, a compact form that suits the foreground and middle of a tank.

Requirement	Anubias nana
Light	Low
CO2	Not required
Difficulty	Easy
Growth rate	Slow
Placement	Epiphyte, foreground to mid

Never bury the rhizome

This is the one rule that matters, and breaking it is the most common way people kill an otherwise indestructible plant. Push the rhizome into the substrate and it rots.

Tie or glue it to rock or wood instead and let the roots find their own grip over a few weeks. Dragon stone works particularly well because its crevices give you somewhere to wedge the rhizome while it attaches.

Slow growth cuts both ways

Slow growth is why Anubias survives conditions that kill faster plants, and it is also why algae finds it. A leaf that takes months to grow has months to accumulate growth on its surface, and older Anubias leaves attract algae for exactly that reason. Its broad, dark leaves are a favourite site for black beard algae.

Removing badly affected old leaves is usually the right move. The plant will not recover a heavily colonised leaf quickly, and taking it off encourages new growth.

It pairs naturally with Java fern and Bucephalandra, which share the same rhizome habit and the same undemanding conditions.

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Anubias questions

Does Anubias need CO2?

No. It grows perfectly well without added CO2, which is a large part of why it turns up in almost every low-tech planted tank.

Why are my Anubias leaves turning yellow or covered in algae?

Older leaves attract algae because the plant grows so slowly. If it is widespread rather than confined to the oldest leaves, look at light and nutrients rather than at the plant. Too much light over a slow grower is a common cause.

Can Anubias be planted in gravel?

Only if the rhizome stays above the surface. You can wedge the roots into gravel, but the rhizome itself must be exposed or it will rot. Attaching it to hardscape is simpler and more reliable.

Bucephalandra is a slow-growing rhizome plant from Borneo, grown for leaves that shimmer blue and purple under good light. It attaches to hardscape rather than rooting in substrate, tolerates low to medium light, and is easy to keep once past the melt that almost every new plant goes through.

Varieties and naming

Plants are sold as Bucephalandra sp. followed by a trade name, because the genus contains a great many forms and the naming in the hobby is not settled. Buy by appearance and by the seller’s variety name rather than expecting a stable binomial.

Expect it to melt

Melt on first transition is normal for Bucephalandra. Leaves die back after the plant moves into your tank, and new growth follows once it adapts to the conditions. It is not a sign you have done something wrong.

The mistake is reacting to it. People pull the plant out, move it, or throw it away during the very phase it needs to be left alone. Leave the rhizome attached, keep conditions steady, and wait. This is the same behaviour Cryptocoryne wendtii shows, and there is more on it in the plant melt guide.

Light, CO₂ and attachment

Requirement	Bucephalandra
Light	Low to medium
CO2	Beneficial
Difficulty	Easy
Growth rate	Slow
Placement	Epiphyte, foreground to mid

Attach it to rock or wood and keep the rhizome above the surface, exactly as with Anubias and Java fern. Added CO2 is not required but does help, and stronger light brings out the colour the plant is bought for.

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Bucephalandra questions

Why is my Bucephalandra melting?

Melt on the first transition into a new tank is normal for this plant. Leave it attached and keep conditions stable, and it will push new leaves adapted to your water.

Does Bucephalandra need CO2?

Not required, but beneficial. It will grow without it, just slowly. Added CO2 and better light are what produce the strong colouring.

Bucephalandra or Anubias?

Both are slow epiphytes with the same rhizome rule. Anubias is the tougher of the two and does better in genuinely low light. Bucephalandra offers smaller leaves and far more colour, at the cost of a melt phase when it arrives.

Cryptocoryne wendtii is the most widely kept crypt in the hobby and one of the best midground plants for a low-tech tank. It grows in low to medium light with no added CO2, roots into the substrate, and comes in green, brown and red forms. It also melts when you first plant it.

Crypt melt, and why not to panic

Plant Cryptocoryne wendtii and within days the leaves may go soft, translucent and fall apart. This is crypt melt, it happens after replanting, and the plant recovers.

What triggers it is a sudden change in conditions, which is what moving between tanks amounts to. The plant discards leaves grown for the old environment and pushes new ones suited to yours.

Leave the roots in the substrate. The roots are what regrow the plant, so digging it up because the leaves have gone is the one action that turns a temporary setback into a dead plant. Keep conditions stable and wait. There is more in the plant melt guide.

Growing it

Requirement	Cryptocoryne wendtii
Light	Low to medium
CO2	Not required
Difficulty	Easy
Growth rate	Slow
Placement	Rosette, midground

It is a rosette plant, so it roots properly into the substrate rather than attaching to hardscape. A nutrient substrate suits it, and it is one of the plants that benefits from a coarse base layer under the soil because it spreads its roots vigorously.

It is a shade plant in the sense that matters for lighting: it grows healthily in low light and does not need a strong fixture to do well. That makes it a good fit for the Walstad method and for any low-tech planted tank.

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Cryptocoryne questions

Why did my Cryptocoryne wendtii melt after planting?

Crypt melt after replanting is normal and the plant recovers. A sudden change of conditions causes it to shed leaves grown for its previous environment. Leave the roots undisturbed and it will regrow.

How long does crypt melt last?

It varies with how different the new conditions are and how settled the tank is. The plant is slow-growing, so recovery is measured in weeks rather than days. Stable conditions matter more than any intervention.

Does Cryptocoryne wendtii need CO2?

No. It grows well in low to medium light without added CO2, which is why it is a staple of low-tech tanks.

Floating aquarium plants sit on the surface with their roots hanging free, and they do two useful jobs at once. They soak up nutrients fast, which starves algae of what it needs, and they shade the tank below, which suits fish and plants that dislike bright light.

Why put them in at all

A new tank is at its most vulnerable to algae in the first few weeks, when the planting is sparse and nothing is competing for nutrients yet. Fast-growing floaters are the standard answer. They take up nutrients quickly and shade the tank, and they do it from day one rather than after they establish.

That makes them a natural fit for the Walstad method, where the whole approach depends on plants outcompeting algae rather than on equipment, and for the jungle style, where a surface canopy is part of the look.

Amazon frogbit

Amazon frogbit, Limnobium laevigatum, is the usual starting point. Round leaves on the surface, long trailing roots beneath, and fast growth.

Requirement	Amazon frogbit
Light	Any
CO2	Not required
Difficulty	Easy
Growth rate	Fast
Placement	Floating

The shading cuts both ways

Shade is the point, and it is also the catch. Floaters grow fast, and a surface that started as partial cover becomes a solid mat if you let it. Everything below then gets less light than you planned for.

That matters most if you are growing anything demanding underneath. A carpet needs strong light reaching the substrate, and a floating canopy is directly at odds with that. Shade plants such as Anubias, Java fern and Cryptocoryne wendtii are the natural companions.

Scoop out handfuls regularly. Treat it as a routine chore rather than a problem, in the same way you would trim a fast-growing stem plant.

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Floating plant questions

Do floating plants help with algae?

Yes, in two ways. They take up nutrients quickly, leaving less available to algae, and they shade the tank, reducing the light algae needs. They are most useful in the early weeks of a new tank.

Will floating plants block too much light?

They can. Left unchecked they form a solid mat and starve the plants below. Thin them regularly, and avoid pairing them with a carpet that needs strong light at the substrate.

Do floating plants need CO2?

No. They sit at the surface with direct access to atmospheric carbon dioxide, which is a large part of why they grow so much faster than submerged plants.

Java fern is one of the hardiest aquarium plants there is. It grows in low light, needs no added CO2, and attaches to wood and rock rather than rooting in the substrate. Along with Anubias it is the plant most often recommended to anyone setting up a first planted tank.

The name has changed

Java fern is currently classified as Leptochilus pteropus, having moved from Microsorum pteropus, and you will still see it sold under the older name almost everywhere. Both refer to the same plant. Aquatic plant naming genuinely does move around, so the trade name is often the more reliable thing to shop by.

Where to attach it

Requirement	Java fern
Light	Low
CO2	Not required
Difficulty	Easy
Growth rate	Slow
Placement	Epiphyte, mid to background

Attach it to wood or rock and leave it alone. Like Anubias, it grows from a rhizome, and burying that rhizome in the substrate will rot it. Tie it on with thread or fishing line, or use gel glue, and the roots will grip on their own within a few weeks.

Its taller, mid-to-background habit makes it a natural fit for Nature Aquarium layouts, where much of the planting is epiphytes lashed to the hardscape, and for the low-tech Walstad method.

Brown or black patches on the leaves

Java fern reproduces by growing tiny plantlets on its leaves, and mature leaves develop dark bumps and patches as part of that process. It looks like disease and usually is not.

Leave those leaves in place until the plantlets are large enough to detach and attach elsewhere. If a leaf is genuinely dying it will go soft and translucent rather than firm and spotted, and that one can come off.

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Java fern questions

Does Java fern need to be planted in substrate?

No, and it should not be. It is an epiphyte that attaches to wood and rock. Burying the rhizome causes it to rot, which is the most common reason a Java fern fails.

Is Java fern easy to care for?

Yes. It tolerates low light, needs no added CO2, and grows slowly enough that it forgives irregular maintenance. The main way to fail with it is to plant it wrongly.

Why is my Java fern growing so slowly?

Because that is what it does. Slow growth is characteristic of the plant, not a sign of a problem. It is also why the plant copes so well with conditions that would kill a fast-growing stem plant.

Java moss is the most forgiving moss in the hobby and one of the easiest aquarium plants of any kind. It attaches to rock and wood, grows in low light with no added CO2, and trims to whatever shape you want. If a moss is going to survive a beginner’s tank, it is this one.

Naming

Java moss is Taxiphyllum barbieri, and it is often still sold as Vesicularia dubyana. The older name has stuck in the trade long after the classification moved on, so both point at the same plant on a shop shelf.

Attaching and shaping it

Requirement	Java moss
Light	Low
CO2	Not required
Difficulty	Easy
Growth rate	Medium
Placement	Attach to rock or wood

Tie a thin layer onto the surface you want it to cover rather than piling it on. A thick clump shades its own base, and the buried portion browns off while the top grows. Spread it thin, secure it with thread or gel glue, and let it knit in.

Trimming is what keeps it looking deliberate rather than shaggy. It takes a trim well and regrows from what you leave behind, which is how people get the neat mossed branches and moss walls you see in Nature Aquarium layouts. Spider wood is a natural host for it.

Java moss or Christmas moss

Christmas moss, Vesicularia montagnei, is the other moss you will meet. It grows denser and tidier than Java moss, with a more structured frond shape, but it wants a little more light, benefits from added CO2, and grows more slowly.

Java moss is the better first moss. Christmas moss is the better-looking one once you can keep it.

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Java moss questions

How do you attach Java moss to wood or rock?

Spread a thin layer over the surface and hold it in place with cotton thread, fishing line or gel glue. It grips on its own within a few weeks, and cotton thread simply rots away once it has.

Why is my Java moss turning brown underneath?

Usually because the layer is too thick. The top shades the bottom, and the lower portion dies off. Thin it out and trim the top regularly so light reaches through.

Does Java moss need CO2?

No. It grows in low light with no added carbon, which is exactly why it is the default recommendation for a first moss.

Rotala rotundifolia is the stem plant people grow when they want colour. Under strong light with added CO2 the tops turn red and orange, and it grows fast enough to fill a background quickly. In lower light it stays green and grows perfectly well, just without the colour it is known for.

Getting the colour

Rotala rotundifolia colours red and orange under high light with added CO2. Both parts matter. Strong light is what triggers the colouring, and CO2 is what lets the plant use that light rather than handing the advantage to algae.

Green Rotala is not a failure. It is what the plant looks like in a low-tech tank, and it grows readily there. If the colour is the reason you want it, be honest about whether your tank can supply the conditions before buying it.

Trimming and propagating

Requirement	Rotala rotundifolia
Light	Medium to high
CO2	Beneficial
Difficulty	Easy to medium
Growth rate	Fast
Placement	Stem, background

Fast growth means regular trimming. Cut the stems and replant the tops, which is the standard way stem plants are propagated and the reason a single pot turns into a full background over a couple of months.

That trim-and-replant cycle is the entire discipline of the Dutch style, where tiered rows of stem plants carry the whole composition and the tidiness is what gets judged.

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Rotala questions

Why is my Rotala rotundifolia green and not red?

Not enough light, most likely. The plant colours red and orange under high light with added CO2, and stays green below that. It is healthy either way.

Does Rotala need CO2?

Not required, but beneficial, and effectively necessary if colour is the goal. It grows without it in medium light as a green background plant.

How do you propagate Rotala?

Cut a stem and replant the top portion in the substrate. It roots readily, and the cut stem branches below the cut, so trimming thickens the stand as well as multiplying it.

Carpet plants are the low, spreading species that cover an aquarium floor in green, the lawn-like foreground that makes a scape look finished. They’re also where beginners most often come unstuck, because the famous ones are the hardest to grow. The trick is choosing a carpet that matches your setup, not the one in the photo.

What makes a plant a “carpet”

A carpet plant stays low and spreads sideways by runners, knitting into a continuous mat across the substrate. That horizontal habit is the easy part. The hard part is that light has to reach all the way to the floor and stay strong there, which is why most true carpets want bright light and, usually, added CO₂.

The five, side by side

Plant	Latin name	Light	CO₂	Difficulty
Staurogyne repens	Staurogyne repens	Med–high	Beneficial	Easy–med
Monte Carlo	Micranthemum tweediei	Med–high	Beneficial→required	Medium
Dwarf hairgrass	Eleocharis acicularis	High	Required	Medium
Dwarf baby tears (HC Cuba)	Hemianthus callitrichoides ‘Cuba’	High	Required	Advanced
Glossostigma	Glossostigma elatinoides	High	Required	Advanced

Start here

If you want a realistic first carpet, Monte Carlo is the one to choose. It is the most forgiving, tolerates slightly less light than the rest, and will even limp along without CO₂ (just slowly). Dwarf hairgrass is the next step: grassy rather than leafy, still very doable, but it really does want strong light to carpet tightly rather than grow tall and sparse.

Approach with caution

Dwarf baby tears (HC Cuba) and Glossostigma are the carpets behind most of the jaw-dropping photos, and most of the beginner failures. Both demand high light and pressurised CO₂. Without that, they grow leggy, lift off the substrate and melt. They’re rewarding once you’ve got a tank dialled in, but they’re the wrong place to begin.

The “carpet without the difficulty” option

Staurogyne repens is a low foreground plant rather than a true carpet, but it gives a similar low, green front edge with far less fuss, tolerating medium light and not strictly needing CO₂. If the demanding carpets feel like a step too far, it’s the sensible compromise.

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Carpet plant questions

What’s the easiest carpet plant for beginners?

Monte Carlo. It is the most forgiving of the true carpets and the most tolerant of less-than-perfect light and CO₂, which is why it is the usual recommendation for a first carpet.

Can you grow carpet plants without CO₂?

A few, barely. Monte Carlo and Staurogyne can manage without it but grow slowly and less densely. The high-light carpets like HC Cuba effectively need CO₂ to carpet at all.

Why won’t my carpet plant spread?

Usually not enough light reaching the floor, or no CO₂. Starved of either, carpets grow upward and leggy instead of spreading sideways, or simply stall.

Monte Carlo (Micranthemum tweediei) is a low, spreading carpet plant with small round leaves, and the most forgiving of the popular aquarium carpets. It’s the one to choose if you want a green lawn without the demands of HC Cuba, tolerating slightly less light and even limping along without pressurised CO₂, just more slowly.

What it needs

• Latin name: Micranthemum tweediei
• Type: carpet / foreground
• Light: medium–high
• CO₂: beneficial, and effectively required for a tight carpet
• Difficulty: medium
• Growth rate: medium

Growing Monte Carlo

Plant small portions spaced out across the substrate rather than one clump. Under good light they send out runners and knit together into a mat. A nutrient-rich substrate gives the roots something to work with. As carpets go it’s among the easier ones, slightly more forgiving than HC Cuba, which is why it’s the carpet most beginners should start with. For the full comparison, see our carpet plants guide.

Getting it to carpet

The two levers are light and CO₂. Strong light reaching the substrate keeps growth low and dense. Added CO₂ tightens it into a proper flat carpet. Without CO₂ it still grows, but slower and looser, and may reach upward rather than hugging the floor. If it starts growing tall, that’s the signal it wants more light down low.

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Monte Carlo questions

Is Monte Carlo good for beginners?

It’s the best carpet to start with. It’s the most forgiving of the popular carpets, though it still wants decent light to stay low and spread, so it is beginner-friendly by carpet standards rather than no-effort.

Does Monte Carlo need CO₂?

It’s beneficial and effectively required for a dense, tight carpet. The plant survives without it, but grows more slowly and less compactly, so most people running it as a true carpet add CO₂.

Monte Carlo or dwarf baby tears?

Monte Carlo has slightly larger leaves and is more forgiving. dwarf baby tears (HC Cuba) gives a finer carpet but is an advanced plant. For a first carpet, Monte Carlo is the safer choice. Dwarf hairgrass is the grassy alternative.

Dwarf hairgrass (Eleocharis acicularis) is a grassy carpet plant that spreads by runners into a fine, lawn-like foreground. It’s a popular Iwagumi carpet, but it comes with one firm condition: it needs strong light reaching the substrate, or it grows tall and sparse instead of carpeting flat.

Conditions it wants

• Latin name: Eleocharis acicularis
• Type: carpet / foreground
• Light: high
• CO₂: required for a true carpet
• Difficulty: medium
• Growth rate: medium

Growing dwarf hairgrass

Split it into small clumps and plant them spaced out across the substrate, and they fill the gaps by sending out runners. A nutrient substrate helps it establish. Trimming the tips encourages it to spread sideways rather than upward. It pairs naturally with an Iwagumi layout, where a single low carpet sets off the stones.

Getting it to carpet, not grow tall

This is the make-or-break point. Dwarf hairgrass won’t carpet tightly without CO₂, and it needs high light reaching the floor. Give it both and it stays low and dense. Starve it of either and the blades stretch upward, thin out and the carpet never closes. If yours is growing tall and patchy, light to the substrate and CO₂ are the first things to check.

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Dwarf hairgrass questions

Does dwarf hairgrass need CO₂?

For a true, tight carpet, yes. It will grow without CO₂, but tends to come in taller and looser rather than forming the dense low lawn it’s grown for.

Why is my dwarf hairgrass growing tall instead of spreading?

Almost always too little light reaching the substrate, or no CO₂. Both push the plant to grow upward in search of light rather than spreading flat. Stronger lighting and CO₂ usually fix it.

Dwarf hairgrass or Monte Carlo?

Hairgrass gives a grassy texture, Monte Carlo a leafy one. Both are medium difficulty, but Monte Carlo is a touch more forgiving on light and CO₂, so it’s often the easier first carpet. See the carpet plants guide to compare.

Dwarf baby tears (Hemianthus callitrichoides ‘Cuba’), usually shortened to HC Cuba, is the smallest-leaved and finest aquarium carpet, and also the most demanding. It produces the dense, manicured green lawn behind countless contest tanks, but it needs high light and pressurised CO₂ to get there, which puts it firmly in advanced territory.

What HC Cuba demands

• Latin name: Hemianthus callitrichoides ‘Cuba’
• Type: carpet / foreground
• Light: high
• CO₂: required
• Difficulty: advanced
• Growth rate: medium

Growing HC Cuba

Plant tiny portions across the substrate and give it bright light and pressurised CO₂ from the start. Under the right conditions it forms a remarkably fine, dense carpet. Under the wrong ones it grows leggy, lifts away from the substrate and melts. It is the classic high-tech carpet that punishes shortcuts. A nutrient substrate and stable conditions matter more here than with any other carpet.

Is it the right carpet for you?

Be honest about your setup. HC Cuba is an advanced, high-tech plant. Without strong light and CO₂ it will fail, and no amount of patience substitutes for those. If you’re starting out or running low-tech, Monte Carlo gives a similar look with far more forgiveness, and dwarf hairgrass is the grassy middle ground. Come to HC once your tank is dialled in. The carpet plants guide lays out the full easy-to-hard order.

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HC Cuba questions

Is dwarf baby tears hard to grow?

Yes. It is an advanced plant. It needs high light and pressurised CO₂ to carpet, and it melts or grows leggy without them, so it isn’t a beginner’s carpet.

Can you grow HC Cuba without CO₂?

Effectively no. CO₂ is required for it to form a carpet. Without it the plant struggles, detaches and typically fails rather than spreading.

HC Cuba or Monte Carlo?

HC Cuba gives a finer, denser carpet but is advanced. Monte Carlo is larger-leaved, more forgiving and the better starting point. Most people are happier beginning with Monte Carlo and moving to HC later.