Reedfish / Ropefish
Erpetoichthys calabaricus
The Prehistoric Snake-Fish of Africa (30-40 cm / 12-15 inches). An incredibly slender, incredibly cute, and absolutely harmless living fossil that belongs to the same family as the massive, armored Bichirs. It looks and moves exactly like a thick shoelace or a swimming eel. It is totally blind, navigating the bottom by 'smelling' for worms using its tiny whiskers. It is extremely social and MUST be kept in groups. Its single, legendary flaw: It is the ultimate escape artist of the aquarium hobby, capable of squeezing its snake-like body out of the tiniest hole in a lid, only to die dried up on the floor.
Water Temperature
22 - 28 °C
pH Value
6 - 7.5
Water type
Freshwater
Tank level
Bottom
Adult size
40 cm
Minimum tank volume
>= 500 L
Minimum group
>= 1
GH
5 - 15 dGH
KH
2 - 7 dKH
TDS
95 - 295 ppm
Conductivity
148 - 461 uS/cm
Species description
Geographical Origin and Habitat: West Africa, between Nigeria and the Congo basin. Populates margins of slow-flowing rivers, marshy areas saturated with reeds and oxygen-poor zones.
Taxonomy and Morphology: Ropefish / Reedfish (Erpetoichthys calabaricus). Polypterid with an impressive snake-like shape (unique in its genus). Possesses fan-shaped pectoral fins used as "hands" to crawl and functional primordial lungs.
Social Behavior: Nocturnal, peaceful, very shy but intensely sociable with its own kind. They often intertwine forming living "knots" of several individuals (must be kept in groups of at least 3-4).
Coloration and Sexual Dimorphism: Olive/brown back, yellowish flanks and belly. No ventral fins; dorsal fins reduced to small isolated spines. Dimorphism: the male has a much thicker and darker anal fin (olive green) compared to the female (ocher/light).
Care, breeding and tankmates
Aquarium Setup: Vital horizontal space (min. 120 cm / 48 inches tank). Fine sand mandatory to avoid injuring the belly. Large PVC pipes hidden in the layout serve as welcome dens. THE LID MUST BE SEALED and weighted (they are the greatest escapologists in aquarium keeping).
Diet and Feeding: Blind carnivore that hunts by smell (external tubular nostrils). Must be fed at dusk with bloodworms, thawed shrimp, strips of white fish, earthworms. Will almost totally ignore dry feeds.
Water Quality: Survives total oxygen crashes (breathes air) but this does not justify polluted water. Prefers neutral-acid pH and zero nitrites. The air above the tank must be warm and humid for the lungs.
Compatibility and Cohabitation: Ideal companion for large peaceful African fish (Pantodon Butterflyfish, Synodontis, large Tetras). Will eat any fish small or slender enough to fit in its mouth, hunting it in its sleep.
Aquarium Breeding: Never documented nor reproduced in commercial circuits; all specimens are wild caught (Wild Caught), which often makes them debilitated at the time of purchase.
Risks and Diseases: Escaping from the tank: if there is a coin-sized hole near the filter pipes, it will get out and die dry on the floor. Very sensitive to medications, copper and dyes (it does not have true scales, but ganoin armor).
Geographic Origin and Distribution
West Africa, between Nigeria and the Congo basin. Populates margins of slow-flowing rivers, marshy areas saturated with reeds and oxygen-poor zones.
Origin
Tropical oceans and reefsNorth AmericaAfrica and Madagascar
Fish profile
- Temperament
- Semi-aggressive
- Despite their snake-like, predatory appearance, they are remarkably peaceful, shy, and inquisitive. They are known to form resting 'piles' with other conspecifics in their favorite hiding spots. Once comfortable, they can become quite tame and will sometimes take food directly from tongs.
- Diet
- Omnivore
- They are nocturnal carnivores requiring a diverse diet of meaty foods to thrive. Live or frozen bloodworms, blackworms, chopped earthworms, and small shrimp are eagerly accepted. Sinking carnivorous pellets can also be offered, but training them to accept dry foods takes patience.
- Life expectancy
- 15-20 years
- The Ropefish is a remarkably long-lived species that can survive for 15 to 20 years in captivity under optimal care. Their long life cycle is supported by a stable aquatic environment, proper nutrition, and a secure aquarium setup. They are resilient fish but are highly sensitive to sudden changes in water parameters and medications containing copper. Ensuring a high-quality environment and proper filtration will help them achieve their maximum lifespan potential.
- Adult size
- 40 cm
- The catalog's scalar value is 40 cm. The FishBase SPECIES table (v25.04 snapshot) source reports a maximum adult measurement of 37 cm for this species, recorded as standard length (SL). The taxonomic record consulted is Erpetoichthys calabaricus (v25.04); male or unsexed record. These figures are not interchangeable: the first is the profile's editorial reference, whereas the second is a published maximum under a specific measurement convention; differences among sources can reflect sex, population, life stage and measuring method.
- Sex ratio
- Group
- They are highly social creatures that thrive in groups and display fascinating communal behaviors. Keeping three or more individuals is highly recommended to encourage them to be more outgoing. The sex ratio is not critical, as they rarely exhibit any aggressive intraspecific behavior.
- Feeding frequency
- Twice daily
- Because of their nocturnal nature, it is best to feed them just before or after turning off the tank lights. Providing food once a day or every other day is usually adequate for healthy adults. Ensure that faster tank mates do not steal all the food before the Reedfish finds it.
- Bioload
- High
- The Reedfish produces a relatively high bioload due to its carnivorous diet and substantial adult length. Powerful canister filters are strongly recommended to process the large amount of waste efficiently. Strict adherence to weekly water changes is necessary to maintain pristine water conditions.
- Flow
- Stagnant
- They originate from slow-moving rivers and heavily vegetated swamps in West Africa. A gentle to moderate water flow is ideal to keep the environment clean without exhausting them. They do not appreciate strong, turbulent currents blowing across the bottom of the tank.
- Reproduction
- Oviparous
- Captive breeding of the Reedfish in home aquaria is exceedingly rare and poorly documented. They require very specific seasonal triggers, such as massive water changes simulating the rainy season. They are egg-layers that scatter their eggs among dense vegetation.
- Compatibility & tankmates
- They are surprisingly peaceful predators that generally ignore fish too large to swallow. They can be safely kept with medium to large peaceful community fish like Congo tetras or severums. Avoid keeping them with small, torpedo-shaped fish that might easily become a midnight snack.
- Tank level
- Bottom
- They are dedicated bottom dwellers, frequently seen slithering across the substrate or resting in tangled roots. Providing a soft, sandy substrate is crucial to protect their delicate undersides from abrasions. They deeply appreciate smooth PVC pipes or dense plant thickets for hiding.
Scientific Parameters & Models
FishBase
Window to the official scientific data of the species
Data synced on: 06/15/2026
- Trophic level
- 3.3 ± 0.4 se
- Resilience
- Low (4.5 - 14 years)
- Generation time
- 1.2 years
- Phylogenetic uniqueness (PD50)
- 1.0002
- Bayesian Length-Weight
- a = 0.00166, b = 3.02
- VulnerabilityLow vulnerability (22 / 100)
Image gallery
Licensed images linked to the species or, when marked, to the closest representative taxon.
Related species
Recommendations grouped by close relatives, companion choices, and similar care.
