Red Cabomba (Cabomba furcata)

Choose red cabomba for colour in a soft-water tank

Red cabomba (Cabomba furcata) is a fast-growing stem plant from tropical Central and South America, also called forked fanwort and still widely sold under its older name Cabomba piauhyensis. Each stem carries whorls of finely divided, feathery leaves that shift from olive green to brown-red and wine-red under strong light, which makes red cabomba one of the few fine-leaved red plants for the back of a planted aquarium.

It belongs to the fanwort family, Cabombaceae. The Flowgrow aquatic plant database lists it from Costa Rica and Panama south through Colombia, Ecuador, Peru, Bolivia, Brazil, Venezuela, Guyana and Trinidad, and in Cuba, in slow-flowing waters with a slightly acidic pH. Wikipedia adds lagoons, ponds, streams, lakes and floodplains, and describes mostly whorled, dark purple submerged leaves and purple flowers. Aquasabi and Flowgrow both rate it difficult; Aquasabi calls it the most demanding of the fanworts.

Decide from the complete care picture

Synonyms you may see on labels include Cabomba piauhyensis (also spelt piauhiensis), Cabomba warmingii and Cabomba pubescens. Red cabomba is a different species from the green Carolina fanwort, Cabomba caroliniana, which may not be sold in England and Wales.

Select a bunch or a pot

One purchase supplies one bunch or one pot of red cabomba, as you select. A bunch is a group of cut stems held together at the base; a pot holds rooted plants that you separate before planting. The number and length of stems vary with the season, and leaf colour depends on the light the plants were grown under, so stems can arrive greener than in the photograph and colour up as they adapt to strong light.

Cabomba is a true water plant. Tropica’s notes on plant production list Cabomba, with Egeria and Vallisneria, among the “pure water plants” that are grown underwater rather than above it, and Flowgrow says this species cannot be grown emersed. The stems are soft and the fine leaves crush easily, so handle them gently and plant them on the day they arrive.

Unpack on the day it arrives

1. Open the bag and lay the stems in a shallow tray of water taken from your aquarium.
2. Check for hitchhikers: Aquasabi notes that plants grown underwater may carry snails or other invertebrates, so rinse each stem and look closely.
3. Remove the band, weight or pot from the base without crushing the stems.
4. Trim damaged bases: cut off any crushed or bare lower section with sharp scissors, just below a whorl of leaves.
5. Plant straight away, following the planting steps further down this page.

Our delivery information explains dispatch days and arrival times, so you can plan to be at home to plant the stems the same day.

Give it strong light, CO2 and full nutrition

Red cabomba stays red and compact only with plenty of light, added CO2 and a steady supply of nutrients. Aquasabi says strong lighting and CO2 addition are important, that it needs a complete supply of macro and micro nutrients, and that a nutrient-rich substrate helps. Wikipedia agrees that carbon dioxide addition is usually necessary, together with high light and regular fertilisation.

Flowgrow puts numbers on it: medium to high light of 0.8 watts per litre or more for stable growth, and 20–40 mg/l CO2, adding that CO2 fertilisation gives a healthy appearance and speeds growth considerably. Watts per litre is a rule of thumb from the era of tube lighting and does not translate directly to modern LEDs, so choose a light sold for demanding, high-light planted tanks. Note that Aquasabi’s quick facts list light as medium while its text calls strong lighting important; we follow the text.

Build a complete nutrient plan

Flowgrow lists darker leaves, reduced growth and long gaps between leaf whorls as the signs of deficiency, and says a nutrient-rich substrate can significantly improve growth. If you see those signs, review the fertiliser before you blame the light. Your fish and shrimp set their own upper limits for nitrate, which are often lower than the plant’s range, so keep the tank within what your animals need.

Keep the water warm and soft

Red cabomba is a warm-water plant. Aquasabi gives 24–30°C and says its optimum temperatures are quite high; Flowgrow gives the same 24–30°C optimum, with a tolerance of 20–35°C. It also wants soft water: Aquasabi lists its maximum hardness simply as soft, and Flowgrow gives pH 5–6.8 and 0–7 °dKH.

Check your tap water before you buy

UK tap water ranges from very soft to very hard between regions, and your water company publishes the hardness for your postcode. Test KH and pH, then compare your readings with the table using our water matcher. If your water is harder than about 7 °dKH, the usual answer is to blend tap water with reverse-osmosis (RO) water to bring hardness down, changing it gradually over several water changes so fish are not shocked.

Our water chemistry guide explains KH, GH and pH, and our guide to pH for tropical fish covers how pH and hardness interact. Outside its soft-water range red cabomba is unlikely to thrive however good the light, so settle the water question before you buy.

Plant stems singly in a background group

Plant red cabomba as a group towards the back or middle of the tank. Aquasabi says it contrasts well with light green plants and Flowgrow notes that it contrasts well with driftwood. Aquasabi gives a stem length of 40–100 cm and recommends keeping it at 20–60 cm, so a taller tank gives you more growth between trims.

Space stems so light reaches the lower leaves

1. Separate the stems one by one; do not plant the bunch as a tight bundle.
2. Strip the lowest whorl or two of leaves from each stem, where it will sit in the substrate.
3. Plant each stem with tweezers, deep enough to hold it upright against the filter flow.
4. Leave a small gap between stems so light reaches the lower whorls; crowded stems shade each other.
5. Feed the roots with a nutrient-rich substrate or root fertiliser near the group.

Fine leaves catch floating debris. Gentle water movement through the group keeps the leaves clean without flattening the stems, and a quick siphon around the base at each water change stops debris from collecting where the stems enter the substrate.

Trim the tops and replant the cuttings

Flowgrow notes that red cabomba grows fast and needs to be cut back frequently. Trimming is also how you multiply it: Flowgrow says terminal cuttings are the easiest way to propagate it, and that when the lower part stays in the substrate a new shoot usually forms at the uppermost node. Aquasabi adds that new shoots appear at the base of older stems.

Use a simple trimming routine

Aquasabi notes that narrow, shield-shaped floating leaves and violet flowers may appear when shoots reach the surface, most visibly in open-topped tanks; Flowgrow says floating leaves and flowers are rare in aquaria. The sources differ on how often it happens, so treat flowering as a bonus rather than a target.

Choose tank mates that share warm, soft water

The best fish for red cabomba come from the same kind of water: warm, soft and slightly acidic. Many South American tetras fit, and the overlap with the plant can be checked value by value. Browse our tetras, the Paracheirodon tetra category and our fish for planted aquariums.

Compare the overlap before you buy

Taken together, a tank kept at 24–27°C and pH 5.5–6.8 sits inside every range in the table. KH and dGH measure different things, so test both. Seriously Fish notes that cardinals seem to do best under fairly dim lighting, which pulls against red cabomba’s need for strong light: give the school shaded areas lower down, under wood or broad leaves, and let the cabomba take the light near the surface. Our cardinal tetra care guide covers the rest of their needs.

Other soft-water companions that leave fine leaves alone include the Ember Tetra, the Zebra Oto and the Amano Shrimp, which picks at algae on the leaves. Avoid plant-eaters: Seriously Fish calls the silver dollar Metynnis argenteus an avid plant-eater, and fine cabomba leaves would not last. Large digging fish uproot stems. Check any proposed mix with our tank mates tool.

Fix fading colour, melting stems and algae

When red cabomba struggles, it shows in the colour first and then in the lower leaves. Work through the causes one at a time and give each change time to show an effect before you make the next.

Pair each symptom with an action

Algae on a fine-leaved plant usually means light, CO2 and nutrients are out of balance rather than one thing being wrong. Our aquarium algae control guide walks through the fixes. Keep notes of each change and the result, so the next decision rests on what you have seen.

Keep fanworts out of UK waters

Red cabomba must never go into ponds, rivers or drains. Its relative Carolina fanwort (Cabomba caroliniana) has been listed as a species of special concern in England and Wales since 3 August 2016, and under the GOV.UK rules it must not be imported, kept, bred, transported, sold or grown. Cabomba furcata is not on that list, and Aquasabi notes it may still be traded in the EU, but Wikipedia records it as invasive in Kerala in India, Kalutara in Sri Lanka, Chini Lake in Malaysia and Taiwan.

Dispose of trimmings the safe way

Aquasabi’s instruction is that aquarium plants must not enter waters or sewage systems and should go only in household waste. OATA advises never releasing aquarium plants into the wild and does not recommend aquarium plants in outdoor ponds, and GOV.UK warns that dumping aquatic plants in the wild may be an offence. Bag spare stems and put them in the bin. Flowgrow lists red cabomba as not winter hardy, so it is not a pond plant in any case.

Answer red cabomba buying questions

Is red cabomba easy to grow?

No. Aquasabi and Flowgrow both rate it difficult. It needs strong light, added CO2 (Flowgrow gives 20–40 mg/l), a complete supply of macro and micro nutrients and soft, warm water at 24–30°C.

Is Cabomba piauhyensis the same as Cabomba furcata?

Yes. Cabomba piauhyensis (also spelt piauhiensis) is an older name for the same plant, as is Cabomba warmingii. The accepted name is Cabomba furcata, and its common names are red cabomba and forked fanwort.

Why is my red cabomba turning green?

Usually the light is too weak. Aquasabi says the intense wine-red tone appears under intense lighting, and the plant stays olive green without it. Stems can also arrive greener than the photograph and colour up as they adapt.

What water does red cabomba need?

Warm, soft and slightly acidic water: Aquasabi gives 24–30°C and soft water, and Flowgrow gives pH 5–6.8 and 0–7 °dKH. In hard, alkaline tap water it is unlikely to thrive without softening the water first.

How tall does red cabomba grow?

Aquasabi gives a stem length of 40–100 cm and recommends keeping it at 20–60 cm by trimming. Plant it towards the back or middle of the tank.

How do I propagate red cabomba?

Take terminal cuttings: cut off the top of a stem and replant it. Flowgrow notes that when the lower part stays in the substrate, a new shoot usually forms at its uppermost node, and Aquasabi adds that new shoots appear at the base of older stems.

Which fish suit red cabomba?

Soft-water fish that leave fine leaves alone, such as cardinal and rummy-nose tetras, ember tetras, otocinclus and Amano shrimp. Avoid plant-eaters such as silver dollars, which Seriously Fish calls avid plant-eaters.

Is red cabomba banned in the UK?

No. Cabomba furcata is not on the GOV.UK list of invasive plants. Its relative Carolina fanwort (Cabomba caroliniana) is: it has been a species of special concern in England and Wales since 3 August 2016. Never release any cabomba into the wild.

Can red cabomba grow in a garden pond?

No. It is a tropical plant that Flowgrow lists as not winter hardy, and OATA does not recommend aquarium plants in outdoor ponds.

Consult the plant references

• Aquasabi: Cabomba furcata (“piauhyensis”), red cabomba — origin, difficulty, temperature, soft water, light, CO2, nutrients, stem length, colour, floating leaves and disposal.
• Flowgrow: Cabomba furcata — synonyms, native localities, light, CO2, temperature, pH, KH and nutrient ranges, deficiency signs, propagation and hardiness.
• Wikipedia: Cabomba furcata — common names, synonyms, family, habitat, leaf and flower description, cultivation and invasive records.
• Tropica: about emersed production of aquarium plants — Cabomba as a pure water plant grown underwater.
• Seriously Fish: Paracheirodon axelrodi — cardinal tetra water values, planted set-ups and lighting.
• Seriously Fish: Petitella rhodostoma — rummy-nose tetra water values.
• Seriously Fish: Metynnis argenteus — silver dollars as avid plant-eaters.
• GOV.UK: invasive non-native plant rules in England and Wales — Carolina fanwort listing and dumping aquatic plants.
• OATA: how to be plant wise — never releasing aquarium plants and outdoor ponds.