Cabomba is a very popular freshwater aquarium plant that grows in both tropical and coldwater tanks, making this an attractive and versatile addition to your display setup. The plant is relatively easy to care for and propagate and is widely available at most fish and aquarium supplies stores for a modest cost.
In this guide, we explain how to ensure that Cabomba thrives in your aquarium, including tips on trimming the plant to keep it tidy and propagating it if you want to grow your own.
What is Cabomba?
Cabomba is an aquatic plant that belongs to the family Cabombaceae. The plant has pretty, divided, fan-shaped leaves, hence one of the plant’s common names, Fanwort.
Cabomba is probably the most common, fastest-growing aquarium plant. Green Cabomba (Cabomba caroliniana) is the most common variety, although the red version, Cabomba furcata, is reputedly one of the most challenging aquarium plants to care for.
Cabomba is also known as:
- Carolina Fanwort
- Green Cabomba
- Brazilian Fanwort
- Purple or Red Cabomba
- Purple or Red Fanwort
- Carolina water shield
- Fish grass
- Washington grass
Cabomba makes a good background plant for fish tanks, as it can grow quite tall.
Te Cabomba plant is found growing wild in southern Brazil, Paraguay, Uraguay, northeastern Argentina, and parts of southeastern South America The east and west coasts of the U.S. also have Cabomba plants growing naturally in some areas.
The plant grows by pushing its roots into the soft muddy substrate of slow-moving or stagnant water, including ponds, lakes, small rivers, ditches, marshes, and streams. Fanwort likes to grow in the shallow water of up to around four feet in depth.
The Cabomba plant has short, fragile rhizomes with erect shoots that are reddish, olive green, or grass-green in color. The shoots bear floating and submerged leaves. The submerged leaves are arranged in pairs on the stem opposite each other, while the floating leaves are linear and arranged alternately.
The plant produces small yellow, purple, or white flowers that arise from the stem tips. In the wild environment, the flowers are pollinated by small nectar-eating flies.
Cabomba Aquatica is generally sold in bunches that are held together at the base by a tight elastic band, purely to hold the bunch together for display.
When choosing your plants, look for those that have lots of green stems that are about six inches or so in length. The leaves should be reddish-purple or green, luxuriant, and bushy. You may notice a few roots growing from the bottom of the stems, as well as signs of new growth, and even a few tiny buds or flowers. Those are all desirable indicators that the plant is in good health.
How to plant Cabomba in your tank
Once you’ve chosen your perfect specimens and taken them home, you’ll want to plant your new purchase in your tank.
Your first job is to remove the tight elastic band from around the base of the stems. Don’t try to pull the band off, as that will probably crack or damage the plant stems. Instead, use a pair of sharp scissors to cut the band.
Once you’ve removed the band, carefully swish the stems in a bucket of clean aquarium water. That helps the plant to shed any loose leaves before you put your new aquarium plants in your tank. Loose leaves can clog your filter intakes or sponge filters or float around the tank, creating an unsightly mess.
When you’ve finished washing the stems, check the area where the elastic bands were. Snip away any damaged portions. Cracked or broken stems will only rot in the aquarium and won’t grow, but you can give the plant a fresh start by removing any damaged parts.
Add an inch or more of nutrient-rich plant substrate to the tank bottom, and gently plant each stem about one inch or so apart so that they have room to grow and sway with the water current. Don’t be tempted to pack the substrate too tightly around the stems, but do try to make sure the stem is secure to prevent the plant from floating away. Plant weights can be used to help keep the stems in situ.
Plant the longer stems toward the back and the shorter ones toward the foreground. If you plant the stems in that way, the plants should grow to create an attractive dense forest effect. After a week or so, the stems will put out roots, quickly digging themselves down into the substrate and holding the plant in place.
You can also use the Cabomba plant as an accent specimen in the midground. For example, try planting small clusters of Fanwort either side of a piece of glass or other decoration to create an attractive feature.
If you have fish species in your tank that appreciate floating plants that they can use as hiding places or safe areas to lay their eggs and rear fry, Cabomba can be useful too.
To float Cabomba caroliniana, all you need to do is drop the stems into the aquarium close to the water surface. Actually, the plant will probably grow better and faster at the surface, as it is closer to the light. The stems will probably produce fine white roots, and some may even flower. However, do be prepared to remove any excess growth that could prevent surface feeders and labyrinth breathers from getting to the water surface.
Care of the Cabomba plant
Caring for Green Cabomba is relatively straightforward, although Purple and Red Cabomba can be decidedly tricky to grow.
The primary cause of problems experienced when growing Cabomba in the aquarium is inadequate lighting.
In low-light conditions, the plant will most likely look fine for a few days, but before too long, the plants begin to disintegrate and die off. Lack of lighting causes the plant to stretch, it’s color fades, and the foliage takes on a yellowish tinge.
Purple and Red Cabomba plants need brighter lighting than the green variety. For optimum growth conditions, you will need to provide the plants with plenty of high wattage lighting per gallon, rather than to give the plants more hours of low-level lighting. The approximate power of fluorescent lamps should ideally be 0.4 to 0.5 watts per gallon of water, and the duration of daylight should not be less than 12 hours.
You may also find that the Cabomba plant benefits from the addition of liquid fertilizer or root tabs that will boost the levels of iron and other minerals in the water. Although it’s not strictly necessary, CO2 supplements can help to promote good growth of Fanwort in the aquarium.
Fanwort is surprisingly particular when it comes to water conditions in the aquarium. The plants prefer very clean tanks with clear, slow-moving water. If the water flow is too fast, the plants often become uprooted, and the leaves are easily damaged.
Ideally, the aquarium pH should be between 6.8 and 7.5, although some hobbyists suggest that the plant will tolerate lower levels than that. The Cabomba plant is tropical, preferring a water temperature of between 720 to 820 Fahrenheit.
Another important aspect of keeping Cabomba is the species of fish and other community residents that are present in the aquarium environment.
These are delicate plants that will not stand up well to the attentions of rough fish species such as goldfish and large cichlids. Also, some species of snails can do a lot of damage to the plants by grazing on their leaves.
Maintenance and trimming
Relocating Cabomba plants
Cabomba plants can grow up to one inch per day when given the right conditions, which can lead them rapidly encroaching on space in your tank.
If you need to relocate the plants, bear in mind that their roots are very fine and string-like, making them extremely delicate and prone to breakage when uprooted. So, if you need to move a Cabomba plant, do not pull the plant out of the substrate. Instead, use your hand to gently scoop up a ball of the substrate from around the plant’s stems, allowing the substrate granules to fall away and drift back to the bottom of the tank.
That way, damage to the plant roots will be minimal. Note that if left undisturbed, Cabomba roots will grow into substantial systems that are very extensive when compared to the size of the parent plant.
How to trim a Cabomba plant
If you provide the Cabomba plant with its optimum growing conditions, you may find that your aquarium becomes overrun with the stuff, stifling other slower-growing plant species. Also, if Green Cabomba reaches the water’s surface, it can block light out of the tank, potentially damaging not only itself but fish and other plants too.
So, you may periodically need to trim the plants. Trimming Cabomba is pretty straightforward. Avoid pulling or tugging on the plant, or you may damage the stems. Use a pair of sharp scissors, rather than your fingers. The idea is to cut the stems cleanly without squashing them or causing them to crack. If you take trimmings that are at least three inches long, you can either float them in the water or plant them in the substrate elsewhere in the tank.
To plant Cabomba, simply push the cut stems gently down into the substrate, ideally in bunches of at least three plants. You may find that you need to use plant weights to keep the stems in place and prevent them from floating up to the top of the tank.
Here are the answers to a few commonly asked questions about growing Cabomba plants.
Q: Does Cabomba need to be planted?
A: No. You can grow the Cabomba plant as a floating specimen as well as a planted one.
Q: How do you propagate a Cabomba?
A: Cabomba is very easy to propagate. Simply snip a three-inch piece of stem from the main plant and either float it on the water surface or plant it gently in the substrate. In a week or so, the plant will put out roots and begin to grow.
Q: Does Cabomba need CO2?
A: Although Cabomba does benefit from the addition of CO2 and plant fertilizer to the water, it doesn’t need CO2 to grow and thrive, provided there’s enough light in the tank.
Q: Is Cabomba a fully submerged plant?
A: Cabomba is a fully submerged plant, although it does put out flowers above the water surface. Although it can survive as a free-floating plant for six to eight weeks, Cabomba is very sensitive to drying out. For that reason, you should ensure that your tank has a lid or cover slide to keep moisture within the tank and prevent the plant from becoming dehydrated.
Cabomba Aquatica is a commonly available and popular plant that’s used as a staple decoration by many aquarists. The plant is readily available from most fish stores and aquarium supplies shops.
The green variety is cheap to buy, although you will pay more for the rarer purple or red type, which is also harder to care for and propagate. That said, as long as you provide the plant with its preferred growing conditions as outlined above, Fanwort, in both its forms, is a rewarding plant to keep in your display tank.