Dwarf Hairgrass Complete Care Guide: Plant Information and Owner’s Guide

Just like your house has a beautiful lawn, your aquarium can too.

Dwarf Hairgrass is one of the most eye catching underwater carpets.

This plant is bright green, has long blades and is very easy to care for. Just a few strands can mature into a beautiful underwater grassland in one month.

Although this is a great beginner carpet plant, there are a few challenges you need to know about.

Keep reading to learn everything you need to know to grow a crop of Dwarf Hairgrass that lasts for years…

Plant Parameter Requirement
Other Common Names Dwarf Spikerush and Needle Spikerush
Scientific Name Eleocharis parvula and Eleocharis acicularis
Family Name Cyperaceae
Distribution Worldwide
Size 4-6 inches tall
Color Green
Care Level Easy
Lifespan 1+ Year
Minimum Tank Size 10 gallons
Tank Mate Compatibility Non-digging fish and invertebrates

Dwarf Hairgrass Overview

Dwarf Hairgrass

There are 2 different species of Dwarf Hairgrass (Eleocharis parvula and Eleocharis acicularis) and both come from the Cyperaceae family of sedges.

While both species have the same care requirements, there are some slight differences between the two. Because these species are often mislabeled as one another at aquarium suppliers, it is important to know how to tell them apart.

  • E. parvula (Dwarf Spikerush): Is found in salt marshes and brackish pools in bays and estuaries. Dwarf Spikerush is a lighter green but grows thicker than Needle Spikerush.
  • E. acicularis (Needle Spikerush): Is purely freshwater grass. This plant is found in wetlands, swamps, and ephemeral pools. Needle Spikerush is longer and curlier than Dwarf Spikerush and it is also a darker shade of green.

While both species are equally easy to care for, our article will focus on the more popular freshwater variety of Dwarf Hairgrass (Eleocharis acicularis).

Both species are found worldwide, from the Americas to Southeast Asia. They have even been found growing near the north and south poles.

This broad distribution means that they can handle a very wide temperature range (starting as low as 55°F).

In aquariums both species are almost always used as carpet plants. Dwarf Hairgrass grows in thick mats along the bottom levels of the tank and provides shelter for any bottom dwellers in your tank. It also makes a great spawning carpet for nursery tanks.

They can grow submerged or partially submerged, and can even be used in paludariums.

If you are looking to grow a thick and dense carpet at the bottom of your tank then E. parvula is the best species to choose.

Expect to pay around $5-$10 depending on how much you need.

Dwarf Hairgrass Appearance

A Planted Tank With Dwarf Hairgrass

There are slight differences in appearance between the 2 species of Dwarf Hairgrass.

At its full height, E. acicularis looks like a mat of curly hair. It grows in a curved shape and can reach a height of around 6 inches. This plant is usually a bright emerald green (just like the grass on your lawn).

E. parvula on the other hand is a deep green color with straight blades. It is a little shorter than E. acicularis and reaches a height of about 4 to 5 inches.

The exact color of your plant will depend on how much light it receives. The more light your plant gets then the brighter green it will be.

Younger shoots of either species may start out very dark green, but turn brighter as they mature.

Size and Growth Rate

This plant grows very quickly but it never gets very tall. After all, it is called Dwarf Hairgrass for a reason!

You can expect it to grow to about 5 inches tall once it is fully grown.

In moderate-high light intensity, it will reach its maximum height in about 4 weeks. This means that it can grow at a rate of 1 to 1.5 inches per week.

If you are growing the plant from seeds rather than shoots, it will take about a week or two extra to reach its full height.

5 Reasons Why Should Keep Dwarf Hairgrass

  1. Carpeting: Fish enjoy carpets in their tanks and Dwarf Hairgrass is one of the best. This plant can carpet all shapes and sizes. As a bonus, it is too thin for your fish to munch on too.
  2. Aquascaping: It is easy to shape and can be used to create a beautiful freshwater aquascape. Because it is so common in nature, this plant helps make your aquarium looks more natural.
  3. Breeding: Certain species of fish and invertebrates will spawn on leaves and grass to help protect their eggs from predators. This dense grass provides a particularly good cover for these tiny eggs and will encourage breeding.
  4. Hardiness: Dwarf Hairgrass is extremely resilient and can adapt to all kinds of water conditions and temperatures. It can be used to furnish a temperate water tank, a tropical biotope, a paludarium, or even a pond.
  5. Easy Care: Not every carpet plant is easy to manage, but this one should give you no trouble at all. Keepers of every skill level should have an easy time with it.

Different Placements of Dwarf Hairgrass

Fish With Dwarf Hairgrass

Generally Dwarf Hairgrass should be placed in the foreground of the tank where it will receive the most attention and light.

It can be planted at the base of a midground or background plant, so long as the plant does not shade it out.

Most people decide to use this plant as a carpet.

Within 4 to 6 weeks a few shoots can grow into a lush underwater lawn that covers the entire bottom level of your tank. You can also use it to carpet the aquatic parts of a paludarium, or bring a little bit of nature home to an outdoor pond.

Unfortunately you cannot grow it over logs or driftwood like you can with other carpet plants (Java Moss). It also cannot grow between sheets of mesh to arrange it in specific layouts.

The other way to grow Dwarf Hairgrass is as a shrub rather than a full carpet.

To do this you can place your shoots further away from each other and trim them back if they begin to intertwine. You can also create a layering effect by trimming your front layers of grass down to shorter lengths.

Dwarf Hairgrass Care Guide

Dwarf Hairgrass is so simple to look after that it almost cares for itself.

It makes an excellent carpet plant for beginners!

The only difficult part is trying to get it to take root, but once it grows in, it can stand up to just about anything.

With this plant the most important thing to consider is the amount of light it receives, and that the tank is not too dirty or crowded for the light to pass through.

Tank Requirements

You will need at least a 10 gallon tank to keep a crop of Dwarf Hairgrass. This plant cannot reach its full height in a smaller tank.

It is extremely temperature hardy and even survives winter temperatures when grown in an outdoor pond. It can handle temperatures down to 55°F! However the ideal water temperature should range between 65-80°F if grown indoors. The optimal temperature for the fastest growth is 70-75°F.

The pH should be about 6.5-7.5 (neutral to slightly acidic). The water hardness depends on which species you grow E. parvula can handle a hardness from 5-15 dGH and E. acicularis can only be grown in freshwater salinities between 4-10 dGH.

Since the roots are so delicate there should be almost no flow at all – a powerful filter can uproot the plant. Consider a sponge filter, HOB, or very low power internal or external filter for this setup. Avoid using an under gravel filter too as these are known to increase turbidity. Sponge filters can be used for very small tabletop setups or breeding tanks. An external filter should only be used for particularly large setups.

It is not necessary but you can include air stones or an air pump if you wish to add a bit of extra oxygen to the water. Of course a HOB filter will also oxygenate the water by creating bubbles.

Most importantly though is light.

This plant does not like to be shaded or to grow in areas where the light cannot fully penetrate. You will need to place it so that it can receive your aquarium lights’ full spectrum. However avoid placing it in direct sunlight unless you are growing it outdoors.

Finally, you must keep the tank very clean. There should be no dirt or sediment that may block out the light.

How To Plant Dwarf Hairgrass

This plant has a very delicate root system so it should only be planted in soft and sandy substrate. You risk damaging the roots if you plant it in hard gravel. Gravel or mud also tends to be too thick for the shoots to push their way through.

The good news is that this is one of the few plants that is safe to grow in a pre-cycled tank, or to add in during the cycling process. It acts as a buffer for the nitrates that will be cycled through your water column.

Once you have placed the substrate you can enrich it with liquid fertilizer or continuous release tabs. Using continuous release fertilizer can help minimize the excess nutrients in your water column.

Next you need to decide are you going to plant from shoots or from seeds.

Generally it is recommenced to plant from shoots because growing from seeds is more difficult and will take longer.

Shoots should be placed about 1 to 2 inches away from one another in the foreground sections of the tank. The carpet can be shaped by trimming the shoots down to the desired length. But if you want to grow them in a specific shape, you will have to plant them in that shape.

Gently bury the roots about 1 inch deep into the substrate and take care not to damage them. Trim the plant immediately afterward, as this will cut away extra weight and allow it to grow quicker.

If you want to grow shrubs instead of a full carpet then you should space your shoots out by about 4 inches.

Trimming Dwarf Hairgrass

Care And Maintenance

This grass is easy to care for but it can grow very quickly.

The growth rate can be a little daunting to an unprepared aquascaper.

Although it does not grow beyond about 6 inches, it can look very messy if it is not trimmed regularly. You can trim the plant both by the top and by the roots, through the latter is a very delicate process.

To trim from the top of the plant, gently grasp the blades with a set of planting tweezers and snip them down to your desired length. To trim from the roots, use your planting tweezers to take hold of the root ball and delicately snip away the excess.

Every 2 or 3 weeks you should perform a 25-30% water change and re-cycle your tank. Your plants will be able to handle the cycling process.

Finally, you will need to look out for algae.

Algae grows starting from the substrate, so your bottom dwelling plants will be the first affected if it gets out of control.

All aquariums need some amount of algae, but too much of it can shade your plants and use up all of the oxygen in the water.

If you have an algae problem then consider adding a few algae eaters before resorting to chemical treatments.

Dwarf Hairgrass Light Requirements

This is definitely not a low light plant.

It needs access to direct light in order to grow and cannot be placed in the shade.

You should only grow this plant under artificial light. Exposing your tank to direct sunlight can raise the temperature and cause algae blooms.

If you want to grow your Dwarf Hairgrass as fast as possible then you should run a light intensity of 3-5 watts per gallon and use a full spectrum LED bulb. Avoid using an intensity above 5 watts per gallon as this will encourage algae to grow.

Make sure that your grass is exposed to light for about 10-12 hours every day.

If your plant is not getting enough light then it will let you know it. Their leaves will turn darker and brown, they will grow slowly and their roots will be very brittle. If all of this is happening to your grass then you should move the plant to an area where it will get more light.

The problem may also lie with the light bulb itself. Aquarium bulbs do not last forever and a dim bulb should be replaced as soon as possible.

5 Common Problems with Dwarf Hairgrass

  1. Blades are turning brown: Blades of grass will turn brown naturally as they die off and make way for new blades. However if your plant looks more brown than green, it is a sign that it is either not receiving enough light or that the water quality is poor. Make sure that your grass is receiving the full spectrum of your aquarium light, and keep your tank clean by performing a water change every 2-3 weeks.
  2. Growing too slow: Dwarf Hairgrass should grow at a rate of about an inch per week. If your plant is growing slowly, then it means it is either poorly fed or in a poorly lit or crowded area. You should always space your aquarium plants out at least 2 inches from one another so that they have room to grow. If this is not the problem, try moving it to another area of the tank where it will receive more light, or increase the amount of fertilizer that you add to the substrate.
  3. Blades are turning yellow: While browning is a sign of poor light exposure, yellow means that your plants are not getting enough nutrients. All plants need nitrogen, phosphate, and potassium in order to grow, so make sure to choose a fertilizer that provides all of these major nutrients.
  4. Turning brittle: This is another problem with the amount of light that the plant receives. Plants that do not receive enough light will turn brittle and eventually break down. To fix it, you will need to move your plant to a more well lit area of the tank.
  5. Will not take root: This plant’s tiny roots are so delicate that they can only grow in very soft and light substrate. If the plants are not taking root then it could mean that the substrate you are using is too rough. The roots will not anchor if they are not buried deep enough too. So make sure that you have buried them at least 1 inch into the substrate. It can take up to a month for new plants to take hold.

Compatibility and Tank Mates

Since this plant is too thin to be eaten, it is compatible with just about anything you can keep in a freshwater tank.

Even Goldfish and Bettas (which are known for eating plants) will not damage your Dwarf Hairgrass!

You can keep it with just about any kind of Nano fish including: Zebra Danios, Harlequin and Chili Rasboras and Guppies. Try adding a school of Cardinal, Flame, or Ember Tetras for more color. The bright green backdrop really makes these little fish stand out.

The grass shelters any bottom dwelling catfish and loaches too. So Kuhli Loaches, Cories, Otos, and Pictus will feel right at home.

You can even grow it in a temperate tank with cooler water species including: Goldfish, Dojo Loaches, and White Cloud Mountain Minnows. You can also keep just about every kind of shrimp with Hairgrass, including: Amano, Cherry, and Bamboo Shrimp. Nerite Snails will also fit right in.

Cichlids are really the only kind of fish to avoid as they are known for uprooting plants. Larger snails can also pose a danger for the same reason.

Dwarf Hairgrass Propagation and Growing

You might be thinking of thickening your current carpet or starting another carpet in a seperate tank.

However propagating this delicate plant on your own can be a major challenge. You cannot snip off cuttings and use them to grow new plants. If you snip off cuttings then you risk damaging their delicate roots.

The best way to propagate this plant is to simply let it grow on its own.

You can speed up the growing process by increasing the water temperature above 70°F.

When well-tended, this plant can last for years and propagate on its own. There is no real need to plant and replant.

Unfortunately if you want to place your Dwarf Hairgrass in a different spot or a different aquarium then you will need to buy new shoots to start another lawn.

New plants should be placed a minimum of 1-2 inches from your current plants. You can add liquid fertilizer to the substrate to help them grow quicker too.

Once these new plants take root they will grow an entirely new carpet in around 4 weeks.

Frequently Asked Questions

How fast does Dwarf Hairgrass grow?

In the right conditions Dwarf Hairgrass will grow between 1-1.5 inches per week.

Can I grow Dwarf Hairgrass without CO2?

If you use a good fertilizer then there is no need to add any CO2 to your water column. This plant grows and propagates itself well enough on its own.


Dwarf Hairgrass is a beautiful and useful plant to keep at the bottom of your aquarium.

Not only does this plant provide shelter for your bottom dwelling fish it also increases the water quality too.

Beginners can successfully keep this plant and it is very easy to trim and shape. It fits into just about any design that you may have planned.

However the real challenge lies in propagation. It is much easier to buy a new plant than it is to try to manually propagate it.

In the right light, temperature, and water conditions, your garden of Dwarf Hairgrass will last for years. What has been your best use for Dwarf Hairgrass?

Let us know in the comments section below…