Anubias congensis Care Guide: Planting, Propagation, Size and Aquarium Requirements

Brief Description

Anubias congensis is a long-used aquarium name for a hardy, slow-growing rhizome plant with elongated green leaves. It is suitable for low-tech aquariums because it does not require intense light, a nutrient-rich substrate or injected CO₂.

The most important rule is simple: never bury the rhizome. Attach the plant to rock or wood, or bury only the roots while leaving the thick horizontal rhizome exposed.

Anubias congensis care at a glance

Is Anubias congensis the correct botanical name?

This name has caused a great deal of confusion in the aquarium hobby. The currently accepted botanical name is Anubias heterophylla Engl. The older name Anubias congensis N.E.Br. is treated as a synonym of Anubias heterophylla.

The aquarium trade makes the situation slightly more complicated because the name “Anubias congensis” has also historically been applied to plants identified as Anubias afzelii. For that reason, a plant sold simply as “Congensis” is not always labelled with botanical precision.

Anubias heterophylla is native to tropical parts of Central and West-Central Africa, including Cameroon, Equatorial Guinea, Gabon, the Republic of the Congo, the Democratic Republic of the Congo and Angola. In nature it occurs in wet tropical habitats such as stream margins and swampy forest understory.

How to plant Anubias congensis in an aquarium

Anubias is a rhizome plant, so it does not need to be planted in aquarium soil. The easiest and safest method is to attach it to a rock, piece of driftwood or another aquarium-safe hardscape.

Step-by-step planting

1. Remove the plant from its pot and carefully remove rock wool or other growing material from around the roots.
2. Identify the rhizome: it is the thick horizontal stem from which both roots and leaf stalks emerge.
3. Choose a shaded or moderately lit position on rock, wood or the substrate surface.
4. Secure the plant without crushing or tightly constricting the rhizome.
5. Make sure the rhizome remains exposed to the water after planting.

Does Anubias congensis need substrate? No. It can grow without any substrate at all when attached to hardscape. If substrate is used, it mainly anchors the roots; the rhizome itself must stay uncovered.

Anubias congensis care requirements

Lighting

Low to moderate light is sufficient. Anubias does not need intense lighting to survive or grow, and its naturally slow growth means older leaves remain in the aquarium for a long time. This gives algae more opportunity to establish on the leaf surface, so very strong light is usually unnecessary.

CO₂ and fertilisation

Injected CO₂ is not required. The plant can be grown successfully in a low-tech aquarium without a pressurised CO₂ system. Additional CO₂ may support stronger or somewhat faster growth, but it does not turn this naturally slow-growing plant into a fast grower.

Because rhizome plants obtain much of their nutrition from the water column, a nutrient-rich substrate is not necessary. In planted aquariums, a complete liquid fertiliser can be used when additional nutrients are needed.

Temperature and pH

Specialist aquatic-plant databases list an optimum temperature around 22-26°C (72-79°F), with a much broader tolerance range, and a pH range of approximately 5.0-8.0. This makes the plant adaptable to many freshwater aquariums.

Broad tolerance should not be confused with a need for extreme conditions. A stable aquarium within normal tropical freshwater ranges is a better target than deliberately keeping the plant near the limits of its reported tolerance.

Growth rate

Anubias congensis grows slowly. Do not expect the rapid weekly growth seen in many stem plants. Slow growth is normal and is one reason the plant requires relatively little trimming.

Algae on the leaves

Slow-growing Anubias leaves can remain on the plant for a long time, which makes them prone to collecting algae when light and nutrient conditions favour algae growth. Avoid unnecessarily intense lighting, keep the aquarium stable and remove badly damaged or heavily algae-covered old leaves when necessary.

How big does Anubias congensis get?

Anubias heterophylla is one of the larger Anubias species used in aquariums. Specialist plant databases give an aquarium height of roughly 25-60 cm (10-24 inches), with a similar potential spread in mature plants. Submerged plants often remain smaller than plants grown emersed in humid conditions.

Because of this size, it normally works best in the midground or background of medium to large aquariums, or as a substantial plant attached to a prominent piece of wood or rock. In a small aquarium it can eventually dominate the available space.

The leaves are typically medium to dark green and range from elliptic to lance-shaped, often with a somewhat wavy margin. The plant can also be grown emersed in a humid paludarium or aqua-terrarium.

How to propagate Anubias congensis

Propagation is done by dividing the rhizome. This is simple, but because the plant grows slowly, there is no advantage in cutting a small or weak specimen too early.

1. Choose a healthy plant with a well-developed rhizome.
2. Use a clean, sharp blade to divide the rhizome.
3. Keep healthy leaves and roots on the new sections whenever possible.
4. Attach each new section to hardscape, or place its roots in the substrate while leaving the rhizome exposed.
5. Be patient. New growth can take time because the species is naturally slow-growing.

Do not bury freshly divided rhizome sections. Keeping the cut rhizome exposed to the water is especially important while the new division establishes.

Fish compatibility

The leathery leaves and sturdy growth of Anubias make these plants useful in aquariums containing fish that disturb or damage more delicate plants. Anubias heterophylla is also listed by specialist plant databases as suitable for cichlid aquariums.

Anubias species are also commonly used in betta aquariums. The plant itself is suitable for a betta tank, although the eventual size of A. heterophylla means that smaller Anubias varieties may be a more practical choice for very small aquariums.

Frequently asked questions

Can Anubias congensis be planted in gravel?

Yes. Bury the roots only and keep the thick rhizome above the gravel.

Does Anubias congensis need substrate?

No. It can be attached directly to rock or driftwood and grown without nutrient-rich substrate.

Does it need CO₂?

No. Injected CO₂ is optional, not a requirement.

How much light does it need?

Low to moderate light is sufficient. High-intensity light is not necessary for this slow-growing plant.

Why is my Anubias rhizome rotting?

A buried rhizome is a common cause. Expose the rhizome and make sure it is not covered by gravel, sand or soil.

How fast does Anubias congensis grow?

Slowly. Long intervals between new leaves can be normal, especially in low-tech aquariums.

Is Anubias congensis safe for bettas?

Yes, Anubias is widely used in freshwater aquariums including betta tanks. For small betta aquariums, however, consider the mature size of this larger Anubias and choose a smaller variety if space is limited.

Sources and taxonomy references

This guide was updated using current botanical and aquarium-plant references, including:

• Royal Botanic Gardens, Kew - Plants of the World Online: Anubias heterophylla
• Flowgrow Aquatic Plant Database: Anubias heterophylla
• Tropica Aquarium Plants: planting rhizome plants
• Aquarium Co-Op: planting rhizome plants