Invasive Species Compendium

Detailed coverage of invasive species threatening livelihoods and the environment worldwide


Heterotis niloticus
(African bonytongue)



Heterotis niloticus (African bonytongue)


  • Last modified
  • 02 November 2019
  • Datasheet Type(s)
  • Invasive Species
  • Host Animal
  • Preferred Scientific Name
  • Heterotis niloticus
  • Preferred Common Name
  • African bonytongue
  • Taxonomic Tree
  • Domain: Eukaryota
  •   Kingdom: Metazoa
  •     Phylum: Chordata
  •       Subphylum: Vertebrata
  •         Class: Actinopterygii
  • Summary of Invasiveness
  • The African bonytongue H. niloticus is a large fish that is widespread in many parts of Africa (Moreau, 1982). This species is native to many parts of Africa, and has...

Don't need the entire report?

Generate a print friendly version containing only the sections you need.

Generate report


Top of page
Heterotis niloticus, the African bonytongue
TitleAfrican bonytongue
CaptionHeterotis niloticus, the African bonytongue
Copyright©Solomon R. David-2013
Heterotis niloticus, the African bonytongue
African bonytongueHeterotis niloticus, the African bonytongue©Solomon R. David-2013


Top of page

Preferred Scientific Name

  • Heterotis niloticus (Cuvier, 1829)

Preferred Common Name

  • African bonytongue

Other Scientific Names

  • Clupisudis niloticus Cuvier, 1829
  • Heterotis adansonii (Cuvier, 1829)
  • Heterotis ehrenbergii (Cuvier, 1829)
  • Heterotis nilotica (Cuvier, 1829)
  • Sudis adansonii Cuvier, 1829
  • Sudis nilotica Cuvier, 1829
  • Sudis niloticus Cuvier, 1829

International Common Names

  • English: African arowana; bony tongue; heterotis

Local Common Names

  • Benin: hwa; kouala; kpote
  • Burkina Faso: fana; rakoko
  • Cameroon: balli; bargi; lareo; noussa; penge; riki; tou
  • Chad: kani; kawi; ngol; ngôlô
  • Congo Democratic Republic: Congo ya sika; muzalazala
  • Czech Republic: fantang nilský
  • Denmark: Afrikansk knogletunge
  • Gabon: no name; poisson sans nom
  • Germany: westafrikanischer Knochenzuengler
  • Ghana: fa
  • Kenya: dese
  • Mali: fana; kondo
  • Nigeria: afo; aika; bahli; bonytongue
  • Philippines: African arowana
  • Senegal: bakkata; bala; balde; dugande; n’diaguel
  • Sudan: katakpi; lek; nauk
  • Sweden: fanntang
  • USA: African bonytongue

Summary of Invasiveness

Top of page

The African bonytongue H. niloticus is a large fish that is widespread in many parts of Africa (Moreau, 1982). This species is native to many parts of Africa, and has also been introduced into many African rivers and lakes to increase fish production (Micha, 1973). The hardiness of this fish, together with its high growth rate, make it a candidate for aquaculture in Africa and it has been transported to a number of countries for this purpose (Welcomme, 1988). Escapees from ponds into the wild have resulted in the establishment of populations which can form the basis for fisheries (Welcomme, 1988).

Froese and Pauly (2012) say that several countries report adverse ecological impacts after introduction, but these ecological impacts were not specified. Froese and Pauly (2012) also mention H. niloticus as a potential pest.

Due to general environmental degradation including oil spillages, pollution and destruction of mangrove swamps, this species has lost an estimated 60% of its previous breeding and nursery habitat in Nigeria. Bake and Sadiku (2005) describe a decline in the population density of H. niloticus from Oyun reservoir, Nigeria, over a two-year period (January 2002-December 2003), and the recorded decline of the species from similar reservoirs in Nigeria indicates that the species is threatened in this environment.

On the IUCN Red List Status, H. niloticus is classified as least concern (LC).

Taxonomic Tree

Top of page
  • Domain: Eukaryota
  •     Kingdom: Metazoa
  •         Phylum: Chordata
  •             Subphylum: Vertebrata
  •                 Class: Actinopterygii
  •                     Order: Osteoglossiformes
  •                         Family: Arapaimidae
  •                             Genus: Heterotis
  •                                 Species: Heterotis niloticus

Notes on Taxonomy and Nomenclature

Top of page

H. niloticus is one of the two living representatives in Africa of the family Osteoglossidae, a lineage within the ancient fish order Osteoglossiformes (the other species is the freshwater butterfly fish, Pantodon buchholtzi). The Osteoglossidae also contains two genera and three species in South America and one genus and three species in the Southeast Asia-East Indies-Australian region (Li and Wilson, 1996).

H. niloticus (Africa) and Arapaima gigas (South America) are considered by many ichthyologists to be the sole members of a separate family, the Arapaimatidae (Ferraris, 2003). Other living Osteoglossiformes include the Mormyridae (Africa), Gymnarchidae (Africa), Pantodontidae (Africa) and Notopteridae (Africa and Asia).


Top of page

Body rather elongate, its depth from 3.5 to 5 times in standard length. Head rather short, length 3.5 to 5 times in standard length. Elongated dorsal and anal fins are posteriorly positioned and end close to the small, rounded caudal fin (Bailey, 1994; Dankwa et al., 1999). Dorsal fin with 32-37, anal with 34-39, rays. Scale formula: 2.5/34-40/6. It lacks ‘feelers’ or mandibular barbels. Dermal bones of skull deeply sculptured. Gill rakers thin and serrate, numbering 33 (young) to 98 on the ceratobranchial (lower limb) and 21 (young) to 76 on the epibranchial (upper limb). These numbers increase with the size of the fish. Number of vertebrae: 66-69 (average usually 67). Maximum reported size: 980 mm SL (weight approx. 10,000 g).

Colour is uniformly greyish or bronze; lips yellowish and eye more or less golden. According to some authors (Daget, 1954; Blache et al., 1964; Moreau, 1982), this coloration may turn into blackish when the fish reach sexual maturity. In the young, posterior parts of anal and dorsal fins sometimes marked with dark longitudinal bands, and scales with a dark oval spot at margins of overlapping zones (Paugy, 1990).

A description is also available in Fishbase (Froese and Pauly, 2012). Reproductive organs are described in detail by Adite et al. (2006).


Top of page

According to Levêque et al., (1990), a distinction must be made between the present area of occurrence resulting from man-made introductions, and its original, natural geographical distribution area. It is generally accepted that the first introductions were made in the early 1950s (Moreau, 1982).

Original (or natural) distribution includes all water-basins of the Nilo-Sudanese region: Corubal, Senegal, Gambia, Volta, Niger, Benue, Chad, Nile and Omo rivers and Lake Turkana (Daget, 1984; Levêque et al., 1990; Paugy, 1990). Areas of introduction of H. niloticus are: artificial reservoirs of Côte d’Ivoire (Bandama and Bia basins); the Cross, Sanaga, Nyong and Ogowe rivers; and Lower and Middle Congo basins (the species was apparently unable to overcome the Kisangani falls to move further upstream), Ubangui and Kasaï (Democratic Republic of Congo) (Paugy, 1990). Also introduced in Madagascar (Stiassny and Raminosoa, 1994).

Distribution Table

Top of page

The distribution in this summary table is based on all the information available. When several references are cited, they may give conflicting information on the status. Further details may be available for individual references in the Distribution Table Details section which can be selected by going to Generate Report.

Continent/Country/RegionDistributionLast ReportedOriginFirst ReportedInvasiveReferenceNotes


AngolaPresentPaugy , 1990
BeninPresentNativeWelcomme, 1975; Welcomme, 1979; Adite, 1987; Levêque et al., 1990; Paugy and et al. , 1994; Adite and Thielen, 1995; Laleye et al., 2003; Lopez-Fernandez et al., 2003; Adite et al., 2005; Adite et al., 2006; Froese and Pauly, 2012
Burkina FasoPresentNativePaugy , 1990; Froese and Pauly, 2012
CameroonPresentNativePaugy , 1990; Froese and Pauly, 2012
Cape VerdePresentIntroducedFroese and Pauly, 2012
Central AfricaWidespreadIntroducedWelcomme, 1988
Central African RepublicPresentIntroducedFroese and Pauly, 2012
ChadPresentNativePaugy , 1990; Froese and Pauly, 2012
CongoWidespreadIntroducedWelcomme, 1988; Froese and Pauly, 2012
Congo Democratic RepublicPresentIntroducedFroese and Pauly, 2012
Côte d'IvoireWidespreadIntroducedTeugels and et al. , 1988; Froese and Pauly, 2012
EgyptPresentNativePaugy , 1990
EthiopiaPresentNativePaugy , 1990; Froese and Pauly, 2012
GabonWidespreadIntroducedWelcomme, 1988; Froese and Pauly, 2012
GambiaPresentNativePaugy , 1990; Froese and Pauly, 2012
GhanaPresentNativeDankwa and et al. , 1999; Froese and Pauly, 2012
GuineaPresentNativeFroese and Pauly, 2012Futa Djallon Gebirge, Guinea
Guinea-BissauPresentNativePaugy , 1990; Froese and Pauly, 2012
KenyaPresentNativePaugy , 1990; Froese and Pauly, 2012
MadagascarWidespreadIntroducedPaugy and et al. , 1994; Froese and Pauly, 2012
MaliWidespreadNativePaugy , 1990; Froese and Pauly, 2012
NigerPresentNativePaugy , 1990; Froese and Pauly, 2012
NigeriaWidespreadNativePaugy , 1990; Froese and Pauly, 2012
SenegalPresentNativePaugy , 1990; Froese and Pauly, 2012
SudanPresentNativeBailey , 1994; Froese and Pauly, 2012White Nile River
TogoPresentIntroducedLévêque and et al. , 1991; Froese and Pauly, 2012Togoville; Borgou, Zan Sargou River alt:160m
UgandaPresentIntroducedPaugy , 1990

History of Introduction and Spread

Top of page

H. niloticus is native in many African countries but has also been introduced in many rivers, natural and artificial lakes and through aquaculture (Micha, 1973). This introduction has been reported by many authors (Iltis, 1961; N’vogo, 1962; Rakotomanampison, 1966; Vincke, 1971; Micha, 1973; Moreau, 1974, 1982; Depierre and Vivien, 1977; Lazard, 1980;Akegbejo-Samsons et al., 2003Nguenga and Brumett, 2003; and Yao et al., 2003).

The first introductions were made in the early 1950s (Moreau, 1982): Nyong Lake (1952) in South Cameroon; Oubangui River (1956) in the Central African Republic; artificial reservoirs (Ayame and Kossou) in Côte d’Ivoire (1959); Pangalames Est, Haut-Plateaux (1963) in Madagascar; and the Congo River and Lake Toumba (1966) in the Democratic Republic of Congo (then Zaire).


Top of page
Introduced toIntroduced fromYearReasonIntroduced byEstablished in wild throughReferencesNotes
Natural reproductionContinuous restocking
Cameroon Cameroon 1952 Yes Depierre and Vivien (1977) From North to South
Cameroon Chad 1955 Froese and Pauly (2012) South Cameroon
Central African Republic Cameroon 1956 Aquaculture (pathway cause) Yes Micha (1973) Introduced in Oubangui River
Congo Cameroon 1950 Yes Froese and Pauly (2012)
Congo Sudan 1950 Yes Froese and Pauly (2012)
Congo Democratic Republic Congo 1950 Yes Froese and Pauly (2012)
Congo Democratic Republic Congo 1966 Yes Moreau (1982) Haut-Plateaux Congo River and lake Toumba
Côte d'Ivoire Cameroon 1959 Aquaculture (pathway cause) Yes Lazard (1980); Moreau (1974) Introduced in artificial lakes Ayamé (1962) and Lake Kossou (1971) and for aquaculture in Bouaké town
Gabon Cameroon 1955 Yes Froese and Pauly (2012)
Madagascar Cameroon 1963 Aquaculture (pathway cause) Yes Rakotomanampisson (1966) For aquaculture at Ivoloina; Pangalames-est, Ogoue River
Philippines 1989 Froese and Pauly (2012)
Togo Yes Froese and Pauly (2012)

Risk of Introduction

Top of page

The complexity of the hydrological regime of many African river and lake systems enhances the risk of introduction and spread in related water bodies of the aquatic system. Migration from source population (lakes) during flooding favours the dispersal of Heterotis in related water bodies and therefore will increase the risk of introduction (Adite et al., 2006). Its importance as a candidate for aquaculture and fisheries also enhances the risk of introduction. Escapees from ponds into the wild resulted in established populations, which form the basis for fisheries (Welcomme, 1988).


Top of page

H. niloticus is a pelagic species, found in freshwater rivers, streams, floodplains, lakes and swamps (Froese and Pauly, 2012). It occurs in shallow water where it feeds on invertebrates, copepods and chironomids. Juveniles are found in swampy places among aquatic vegetation; adults live in the open water of rivers and lakes, where they can be found in the pelagic zone as well as the littoral zone (Moreau, 1982). The species can survive in deoxygenated waters (Moreau, 1982; Adite et al., 2006).

Habitat List

Top of page
Terrestrial ‑ Natural / Semi-naturalWetlands Secondary/tolerated habitat Natural
Lakes Principal habitat Natural
Reservoirs Principal habitat Productive/non-natural
Rivers / streams Principal habitat Natural
Ponds Secondary/tolerated habitat Productive/non-natural
Estuaries Secondary/tolerated habitat Natural
Lagoons Secondary/tolerated habitat Natural

Biology and Ecology

Top of page


Carrera et al. (2011) reported the development of nine polymorphic nuclear-encoded microsatellite DNA loci for the African bonytongue (H. niloticus). They tested these primers with a sample of 40 individuals from two natural populations in Benin, West Africa. The number of alleles for the nine microsatellites ranged from 2 to 9, observed heterozygosity from 0.125 to 0.882, and expected heterozygosity from 0.156 to 0.810. No significant deviations from Hardy-Weinberg equilibrium or linkage disequilibrium were observed, and there is no indication of null alleles. 

Reproductive Biology 

Bonytongues (H. niloticus) select sites and construct their nests in shallow marginal areas within the aquatic vegetation at the floodplain. Nests average 116 cm in diameter (range 77–165 cm) and occur at an average water depth of 60 cm (range 40–86 cm). Height of submerged and emergent vegetation surrounding nests ranges from 30 to 135 cm (mean = 89 cm), and the diameter of nest entrances range from 20 to 47 cm (mean = 33 cm). Between 1 and 7 days posthatch, larvae have large yolk sacs and are incapable of significant movement, and thus are particularly vulnerable. When nests containing newly hatched larvae are disturbed, both parents take larvae into their mouths for transportation to another location (Adite et al., 2006). The number of larvae per nest ranges from 3953 to 6125 (mean = 5028). Tending of nests and broods occurs from the time of hatching until juveniles disperse from the nest. Recruitment age is estimated as 6 months (Moreau, 1982), the age at which Heterotis initiates migration from reproductive sites to open water or to floodplains.

In Lake Kan and Lake Ayame in Côte d’Ivoire, the proportions of males and females were 48% and 52%, and 33% and 67%, respectively (Moreau, 1982). In Lakes Tamatave and Manakane in Madagascar, the proportions of males and females were 47% and 53%, and 56% and 44%, respectively (Moreau, 1982). In the Lake Hlan – River Sô system of Benin, of the 1461 specimens sampled, 53.7% were males and 46.3% were females (Adite et al., 2006).

H. niloticus matures at 2 years (Moreau, 1982) and has relatively large eggs (2.5–3.0 mm) and moderate batch fecundity (2700–27,500) for a fish of its size. Consequently, the species displays a life history strategy that is closer to the equilibrium endpoint than the periodic endpoint (Winemiller and Rose, 1992), which implies that parental care is essential for early life stage survivorship and levels of recruitment needed for long term population viability (Winkle et al., 1993; Rose et al., 2001). 

Lowest and highest fecundities recorded for individual fish were 2697 (545 mm TL, 500 mm SL, 1.33 kg) and 27,508 oocytes (815 mm TL, 735 mm SL, 4.65 kg), respectively (Adite et al., 2006). In Lake Oubangui, Micha (1973) reported fecundity between 3572 and 15,246 oocytes. Fecundity increased with body length and body weight. Ovarian weight increased with body size. The number of oocytes per gram of ovary was not influenced by body size. Relative fecundity (number of oocytes per gram of body mass) revealed no general association with body size (Adite et al., 2006). 

In the Lake Hlan – River Sô system of Benin, the Gonadosomatic Index (GSI) was significantly affected by season for both males and females. GSI peaked during the wet season (May to August), then declined progressively throughout the flood period until the beginning of the dry season in November to December. These indicated that the spawning period of bonytongues was restricted to the wet and flood period margins (Adite et al., 2006). 

Detailed descriptions of structure and development of reproductive organs are given by Adite et al. (2006)

Physiology and Phenology

Reizer (1964) reported an age at maturity of 20 months for H. niloticus reared in fish ponds. In Madagascar, H. niloticus matured between 2 and 2.5 years old (Moreau, 1982).

Micha (1973) cited by Moreau (1982) reported a size at first maturity of 400 mm (600 g) in Lake Oubangui. The size at first maturity for H. niloticus in the Lake Hlan – River Sô system of Benin was about 575 mm total length (TL) for both male and female. The smallest mature male was 560 mm TL (515 mm Standard Length, 1490 g), and the smallest mature female was 545 mm TL (499 mm Standard Length; 1770 g) (Adite et al., 2006).

In the Lake Hlan – River Sô system of Benin, Length-Weight regressions by habitat, sex, size and season were significant (P < 0.0001) with correlation coefficients ranging from 0.74 to 0.99 and slopes from 2.74 to 4.05, indicating allometric growth. In this aquatic system, body condition varied according to habitat (lake vs river channel) and season (dry, wet, flood ) (Adite et al., 2006). 


Possibly between 5 and 10 years (Moreau, 1982). 

Activity Patterns

H. niloticus selects sites and constructs nests in shallow marginal vegetated areas of the lake. However, during the very high flood period, when water depth became too great at these locations, most bonytongues abandoned their original nests and new nests appeared along newly flooded lake margins (Adite et al., 2006).

Moreau (1982) reported migration during reproduction. A source subpopulation of H. niloticus comprised of spawners, and a sink subpopulation comprised of immature fish (juveniles, sub-adults), have been identified in a permanent lake (Lake Hlan in Benin) and a periodic floodplain (Sô River floodplain) respectively (Adite et al., 2006). 


H. niloticus in the River Kaduna flood plain in Nigeria is considered to be predominantly planktivorous (Bake and Sadiku, 2005). However, the diet reported by Adité et al. (2005) along with the relative gut length trend (relative gut length was inversely related to body size of Heterotis) support that H. niloticus is an omnivore rather than a detritivore, a planktivore or a specialist invertebrate feeder. The different food habits of Heterotis in different habitats suggest a degree of trophic plasticity of this species.

In the Lake Hlan – River Sô system of Benin, smaller H. niloticus tended to consume insect larvae and microcrustacae and larger fish tended to consume hard seeds and adults. The thick-walled gizzard of H. niloticus, which generally contained sand, aids digestion of seed coats. Detailed information on diet composition is given by Adité et al. (2005).

Diet breadth tended to increase with size, indicating that bonytongues consume a broader range of food resources as they grow (Adité et al., 2005).

Lauzanne (1972) in Lake Chad recorded the diet of H. niloticus as: fish 2.2%, aquatic insects 19.3%, ostracods 23%, seeds 14%, and zooplankton 11.3%.

Natural Food Sources

Top of page
Food SourceFood Source DatasheetLife StageContribution to Total Food Intake (%)Details
algae Adult/Broodstock/Fry/Larval 0-21.87
insects All Stages 4.29-64.44
microcrustacea All Stages 0.54-27.07
molluscs Adult/Broodstock 0.07-11.59
sands and detritus Adult/Broodstock 11.31-43.30
seeds Adult/Broodstock 5.62-38.66


Top of page
A - Tropical/Megathermal climate Preferred Average temp. of coolest month > 18°C, > 1500mm precipitation annually
Af - Tropical rainforest climate Preferred > 60mm precipitation per month
Am - Tropical monsoon climate Preferred Tropical monsoon climate ( < 60mm precipitation driest month but > (100 - [total annual precipitation(mm}/25]))
As - Tropical savanna climate with dry summer Preferred < 60mm precipitation driest month (in summer) and < (100 - [total annual precipitation{mm}/25])
B - Dry (arid and semi-arid) Tolerated < 860mm precipitation annually
BS - Steppe climate Tolerated > 430mm and < 860mm annual precipitation
BW - Desert climate Tolerated < 430mm annual precipitation

Latitude/Altitude Ranges

Top of page
Latitude North (°N)Latitude South (°S)Altitude Lower (m)Altitude Upper (m)
18 22

Water Tolerances

Top of page
ParameterMinimum ValueMaximum ValueTypical ValueStatusLife StageNotes
Conductivity (µmhos/cm) 99.45 Optimum Sô River, Benin (Adite et al., 2006)
Depth (m b.s.l.) 0.42 Optimum Sô River, Benin (Adite et al., 2006)
Dissolved oxygen (mg/l) 0.4 4.5 Optimum Sô River, Benin (Adite et al., 2006)
Iron (mg/l) 1.04 Optimum Sô River, Benin (Adite et al., 2006)
Nitrite (mg/l) 0.002 Optimum Sô River, Benin (Adite et al., 2006)
Salinity (part per thousand) 0 Optimum Sô River, Benin (Adite et al., 2006)
Suspended solids (mg/l) 46.7 Optimum Sô River, Benin (Adite et al., 2006)
Turbidity (JTU turbidity) 40 Optimum Sô River, Benin (Adite et al., 2006)
Water pH (pH) 5.4 Optimum Sô River, Benin (Adite et al., 2006)
Water temperature (ºC temperature) 15 30 Optimum Froese-Pauly, 2012

Natural enemies

Top of page
Natural enemyTypeLife stagesSpecificityReferencesBiological control inBiological control on
Apiosoma Parasite to genus
Heterotesia voltae Parasite to species
Lernaeogiraffa Parasite All Stages to genus
Myxobolus Pathogen
Tenuisentis Pathogen

Notes on Natural Enemies

Top of page

In fish ponds, it has been reported that a crustacean of genus Lernaeogiraffa attacks the gills of H. niloticus and may affect 40% of the population. In fish farming in Ghana, the parasite Lernea has been found (Micha, 1973). In Lake Ougbangui, the protozoa, Glossatella sp. caused larva death by asphyxiation. In the Oueme River in Benin, Euzet and Dossou (1979) reported the presence of Heterotesia voltae on the gills of H. niloticus. Sporozoa infection (Myxobolus sp.), Tenuisentis sp. infection and parasitic infestations (protozoa, worms, etc.) have been reported (Paperna, 1996).

Means of Movement and Dispersal

Top of page

Accidental Introduction

No accidental introduction has been recorded. However, the high interconnection of African rivers and lakes systems leading to a complex hydrological regime could allow natural spread of H. niloticus (Adite, 2007). For example in Benin, according to Froese and Pauly (2012), H. niloticus was introduced in the Mono River. However, it is also possible that its presence in this river may result from a natural introduction from adjacent water bodies. 

Intentional Introduction

H. niloticus has been intentionally introduced in many African rivers, natural and artificial lakes for fisheries, and is also used in aquaculture and introduced for this purpose (Micha, 1973), as detailed in the History of Introduction section. The first introductions were made in the 1950s.

Pathway Causes

Top of page
CauseNotesLong DistanceLocalReferences
AquacultureDeliberate Yes Yes Micha, 1973
Escape from confinement or garden escapeNatural Yes
FisheriesDeliberate Yes Yes Moreau , 1982
Flooding and other natural disastersNatural Yes
FoodDeliberate Yes Yes
ResearchDeliberate Yes Yes Adite et al., 2005

Pathway Vectors

Top of page
VectorNotesLong DistanceLocalReferences
Aircraft Yes
Aquaculture stock Yes Yes Micha, 1973
Land vehicles Yes

Impact Summary

Top of page
Economic/livelihood Positive
Human health Positive

Economic Impact

Top of page

In many African rivers and lakes, H. niloticus is intensively exploited compared with other fish species, and some fishermen go out for fishing only to hunt H. niloticus (Moreau, 1982; Adite, 2007).H. niloticus is a large species with high commercial value (Micha, 1973; Moreau, 1982; Adite, 2007). About 682 tons of H. niloticus is caught annually in Benin, valued at US$500,000 (Adite, 2007). Gbaguidi and Pfeiffer (1996) estimated the harvest of bonytongues in Benin at 742 tons.

Women buy H. niloticus from fishermen on lakes and rivers and sell it in local markets or abroad: women from other countries sell H. niloticus to Nigeria where it fetches a high price.

Farming of H. niloticus is widespread in many African countries, including Côte d’Ivoire (Yao et al., 2003), Cameroon (Nguenga and Brummett, 2003), Nigéria (Olanyan and Zwilling, 1963; Akegbejo-Samsons et al., 2004), and Benin (Adite, 2007). Moreau (1982) reported a yield of 2 t/ha/year from Heterotis farming with individuals weighing about 1 kg.

Environmental Impact

Top of page

H. niloticus inhabits fresh water habitat in associations with many other species. Negative impacts on habitats and biodiversity have not been recorded because of its omnivorous feeding habit and its trophic plasticity (Adité et al, 2005). Froese and Pauly (2012) report that several countries experience adverse ecological impacts after introduction, but these ecological impacts were not specified. Froese and Pauly (2012) also mention H. niloticus as a potential pest.

More research is required to evaluate the impact of H. niloticus introductions on other species and on river and lake habitats.

Risk and Impact Factors

Top of page Invasiveness
  • Invasive in its native range
  • Proved invasive outside its native range
  • Has a broad native range
  • Abundant in its native range
  • Highly adaptable to different environments
  • Is a habitat generalist
  • Tolerates, or benefits from, cultivation, browsing pressure, mutilation, fire etc
  • Tolerant of shade
  • Capable of securing and ingesting a wide range of food
  • Highly mobile locally
  • Benefits from human association (i.e. it is a human commensal)
  • Long lived
  • Fast growing
  • Has high reproductive potential
Impact mechanisms
  • Rapid growth


Top of page

H. niloticus is of high commercial value for fisheries. Fishing of H. niloticus takes place in all African countries where the species occurs. In Bénin H. niloticus is caught in Lake Nokoué, Lagoon Porto-Novo, Lake Doukonta, Lake Togbadji, Lake Hlan, Lake Toho, Lake Ahouangan, Lake Dati, Lagune Toho-Todougba, Sô River, Ouémé River; Mono River, Couffo River, and Sazué River. 

Research on the exploitation of H. niloticus for aquaculture is ongoing in many African countries. In Côte d’Ivoire, Yao et al. (2003) report work on rearing density, growth and survival. Nguenga and Brummett (2003) evaluate the establishment of H. niloticus in Nyong River in Cameroon. Work in Nigeria includes the evaluation of aquaculture potential of H. niloticus (Olanyan and Zwilling, 1963), and reproduction and aquaculture potential of Heterotis niloticus reared in fish ponds in southwest Nigéria (Akegbejo-Samsons et al., 2004). Preliminary results on the effects of weaning age on survival and growth of H. niloticus in Benin are reported by Adite (2007). Problems for aquaculture development include artificial reproduction and larval rearing (weaning).

H. niloticus is also used commercially as an aquarium species (Froese and Pauly, 2012).

Uses List

Top of page

Drugs, stimulants, social uses

  • Religious


  • Botanical garden/zoo
  • Capital accumulation
  • Laboratory use
  • Pet/aquarium trade
  • Ritual uses

Human food and beverage

  • Beverage base
  • Eggs
  • Meat/fat/offal/blood/bone (whole, cut, fresh, frozen, canned, cured, processed or smoked)
  • Oil/fat


  • Skins/leather/fur

Medicinal, pharmaceutical

  • Source of medicine/pharmaceutical

Similarities to Other Species/Conditions

Top of page

Like the African catfish Clarias gariepinus, Heterotis spawns during the flooding period during which both species are abundant. For both species, reproduction in captivity is difficult and both are omnivorous and feeding on benthic and pelagic prey (Moreau, 1982; Adite et al., 2005).


Top of page

Adite A, 1987. Données préliminaires sur l'écologie et la production halieutique du complexe lagunaire Toho-Ahouangan ([English title not available])., Benin: Faculté des Sciences Agronomiques, Université Nationale du Bénin, 157 pp. [Thèse d'Ingénieur Agronome.]

Adite A, 2007. Ecologie de Heterotis niloticus (Osteoglossiformes: Osteglossidae) du système fluvio-lacustre rivière Sô-lac Hlan (Sud-Bénin): Conservation et intérêt pour l'aquaculture ([English title not available]). Cotonou, Benin: Université d'Abomey-Calavi, FAST/UAC, 239 pp. [Thèse de doctorat unique.]

Adite A; Thielen RVan, 1995. Ecology and fish catches in natural lakes of Benin, West Africa. Environ. Biol. Fish, 43:381-391.

Adite A; Winemiller KO; Fiogbe ED, 2005. Ontogenetic, seasonal, and spatial variation in the diet of Heterotis niloticus (Osteoglossiformes; Osteoglossidae) in the Sô River and Lake Hlan, Benin, West Africa. Environmental Biology of Fishes, 73:367-378.

Adite A; Winemiller KO; Fiogbe ED, 2006. Population structure and reproduction of the African bonytongue Heterotis niloticus in the Sô River-floodplain system (West Africa): implications for management. Ecology of Freshwater Fishes, 15:30-39.

Akegbejo-Samsons FO; George A; Agbon AO, 2003. Growth, reproduction and aquaculture potential of the African bonytonque fish (Heterotis niloticus) in ponds and reservoirs in coastal south-west states of Nigéria. In: International Conference of the Panafrican Fish and Fisheries Association, Cotonou, Benin, 10-14 November 2003.

Aubenton F, 1955. [English title not available]. (Etude de l'appareil branchiospinal et de l'organe suprabranchial d' Heterotis niloticus (Cuv).) Bulletin de l'Institut Français d'Afrique Noire Noire (A Sci. Nat.), 17:1179-1201.

Bailey RG, 1994. Guide to the fishes of the River Nile in the Republic of the Sudan. J. Nat. Hist., 28:937-970.

Bake GG; Sadiku SOE, 2005. 19th Annual Conference of the Fisheries Society of Nigeria (FISON), 29 November - 03 December 2004, Ilorin, Nigeria (Food and feeding habits of Heterotis niloticus from River Kaduna floodplain)., In.

Balon EK, 1975. Reproductive guilds of fishes: a proposal and definition. J. Fish. Res. Board Can., 32(6):821-864.

Blache J, 1964. [English title not available]. (Les poissons du bassin du Tchad et du bassin adjacent du Mayo Kebbi. Étude systématique et biologique.) Mém. O.R.S.T.O.M, 4(2):483.

Brummett RE, 2000. Research on improved germplasm for aquaculture at the ICLARM Regional Research Center for Africa and West Asia and a note on the domestication of Heterotis niloticus. In: Biodiversity and sustainable use of fish in the coastal zone [ed. by Abban, E. K. \Casal, C. M. \Falk, T. M. \Pullin, R.]. 56-58. [ICLARM Conference Proceedings 63.]

Carrera E; Renshaw MA; Winemiller KM; Hurtado LA, 2011. Isolation and characterization of nuclear-encoded microsatellite DNA primers for the African bonytongue, Heterotis niloticus. Conservation Genetics Resources, 3:537-539.

Daget J, 1954. [English title not available]. (Les poissons du Niger supérieur.) Mém. I.F.A.N, 36:391.

Daget J, 1957. [English title not available]. (Mémoire sur la biologie des poissons du Niger moyen. Reproduction et croissance d' Heterotis niloticus (Erh.).) Bulletin de l'Institut Français d'Afrique Noire (A Sci. Nat.), 19:295-329.

Daget J, 1984. Osteoglossidae. In: Daget J, Gosse JP, Thys van den Audenaerde DFE, eds. Check-list of the freshwater fishes of Africa (CLOFFA). Volume I. ORSTOM, Paris and MRAC, Tervuren, 57-58.

Daget J; d'Aubenton F, 1956. [English title not available]. (Heterotis niloticus peut être un poisson de pisciculture?.) Publ. Cons. Sci. Afr. Sud Sahara /Comm. Coop. Tech. Africa, 25:109-11.

Dankwa HR; Abban EK; Teugels GG, 1999. Freshwater fishes of Ghana: identification, distribution, ecological and economic importance Ann. Mus. R. Afr. Centr., Sci. Zool., 283:53.

Depierre D; Vivien J, 1977. A success by the forestry service in Cameroon: the introduction of Heterotis niloticus in the Nyong. (Une reussite du service forestier du Cameroun. L'introduction d'Heterotis niloticus dans le Nyong.) Bois et Forets des Tropiques, No. 173:59-68.

Euzet L; Dossou C, 1979. Anatomy and taxonomic position of the monogenean Heterotesia voltae Paperna, 1969. (Anatomie et position systematique du Monogene Heterotesia voltae Paperna, 1969.) Bulletin de l'Institut Fondamental d'Afrique Noire, 41(3):505-512.

FAO, 2005. Fishery records collections. FIGIS data collection. Rome, Italy: Inland Water Resources and Aquaculture Service (FIRI), FAO-FIGIS.

FAO/UNDP, 1970. Report to the government of Nigeria on the fishery investigation on the Niger and Benue rivers in the Northern region and development of a programme of riverine fishery management and training. Based on the work of M. Motwani, inland fishery biologist. Rep. FAO/UNDP (TA), 2771. Rome, Italy: FAO, 196 pp.

Ferraris CJ, 2003. Family Arapaimatidae (Bonytongues). In: Check List of the Freshwater Fishes of South and Central America [ed. by Reis, R. E. \Kullander, S. O. \Ferraris, C. J.]. Porto Alegre, Brazil: EDIPUCRS, 582-588.

FishBase, 2004. Heterotis niloticus. Main ref. Paugy D, 1990. Osteoglossidae. In: Lévêque C, Paugy D, Teugels GG, eds. Faune des poissons d’eaux douces et saumâtres de l’Afrique de l’Ouest. Tome 1. Coll. Faune Trop. n°XXVIII. Paris, France: Musée Royal de l’Afrique Centrale, Tervuren and Éditions de l’ORSTOM, 114-115. Online at Accessed 28 September 2004.

Froese R; Pauly D, 2012. FishBase. FishBase.

Gbaguidi AS; Pfeiffer V, 1996. Statistiques des Pêches Continentales, Année 1995 ([English title not available]). Cotonou, Benin: GTZ-GMBH & Direction des Pêches.

Greenwood PH, 1973. Interrelationships of Osteoglossomorphs. In: Interrelationships in fishes [ed. by Greenwood, P. H. \Miles, R. S. \Petterson, C.]. London, UK: Academic Press, 307-320.

Hermens M; Daffé M; Vandewalle P, 2007. Observations of the reduction of external gill filaments during larval development in Heterotis niloticus. Belgian Journal of Zoology, 137(2):247-249.

Hickley P; Bailey RG, 1987. Food and feeding relationships of fish in the Sudd swamps (River Nile, southern Sudan). J. Fish Biol., 30:147-159.

Iltis A, 1961. Observations sur le comportement de Heterotis niloticus à la station piscicole de Kokondekro, Bouaké ([English title not available]). Bouaké, C6te d'lvoire: Centre Technique Forestier Tropical, 11 pp.

Ita EO, 1984. Kainji (Nigeria). p. 43-103. In: Kapetsky JM, Peter T, eds. Status of African reservoir fisheries. CIFA Tech. Pap., 10, 326.

Kimpe Pde, 1967. Heterotis niloticus: Recherche sur la survie des alevins ([English title not available]). Bouaké, Cote d'lvoire: Centre Technique Forestier Tropical, 18 pp.

Laleye P; Chikou A; Teugels G; Vandewalle P; Philippart JC, 2003. [English title not available]. (Biodiversité et statut et des poissons du fleuve Ouémé au Benin.) In: International Conference of the Panafrican Fish and Fisheries Association, Cotonou, Benin, 10-14 November 2003.

Lauzanne L, 1976. [English title not available]. (Régimes alimentaires et relations trophiques des poissons du lac Tchad.) Cahiers ORSTOM, série Hydrobiologie, 10:267-310.

Lazard J, 1980. La pêche en eau libre et le développement de la pisciculture dans les eaux continentales ivoiriennes ([English title not available]). Montpellier, France: Université des Sciences et Techniques du Languedoc, 253 pp. [Thèse de Doct. Ing.]

Levêque C; Paugy D; Teugels GG, 1990. Faunes des poissons d'eaux douces et saumâtres et de l'Afrique de l'Ouest. Tome 1 ([English title not available]). Paris, France: Editions ORSTOM/MRAC.

Levêque C; Paugy D; Teugels GG, 1990. Faunes des poissons d'eaux douces et saumâtres et de l'Afrique de l'Ouest. Tome 2 ([English title not available]). Paris, France: Editions ORSTOM/MRAC.

Lévêque C; Paugy D; Teugels GG, 1991. Annotated check-list of the freshwater fishes of the Nilo-sudan river basins, in Africa. Rev. Hydrobiol. Trop., 24(2):131-154.

Li GQ; Wilson MVH, 1996. Phylogeny of Osteoglossomorpha. In: Interrelationships of Fishes [ed. by Stiassny, M. L. J. \Parenti, L. R. \Johnson, G.]. New York, USA: Academic Press, 163-174.

Lopez-Fernandez H; Winemiller KO; Adité A; Arrington DA; Layman CA, 2003. Fresh water fish diversity in Benin, West Africa, and challenge for its conservation. In: International Conference of the Panafrican Fish and Fisheries Association, Cotonou, Benin, 10-14 November 2003.

Lowe McConnell RH, 1975. Fish communities in tropical freshwaters. London, UK: Longman.

Lowe McConnell RH, 1987. Ecological studies in tropical fish communities. Cambridge, UK: Cambridge University Press, 382 pp.

Micha JC, 1973. Etude des populations piscicoles de l'Ubangui et tentatives de sélection et d'adaptation de quelques espèces a l'étang de pisciculture (Study on fish populations in Ubangui and tentative selection and adaptation of some species to pond aquaculture). Nogent-sur-Marne, France: Centre Technique Forestier Tropical (CTFT), 147 pp.

Moreau J, 1974. [English title not available]. (Premières observations écologiques sur la reproduction d'Heterotis niloticus (Osteoglossidae).) Annales d'Hydrobiologie, 5:1-13.

Moreau J, 1982. [English title not available]. (Exposé synoptique des données biologiques sur Heterotis niloticus (Cuvier, 1829).) Food and Agriculture Organization Synopsis des Pêches, 131:1-45.

Moreau J, 1982. Exposé synoptique des données biologiques sur Heterotis niloticus (Cuvier, 1829). FAO Fish. Synop., 131:44.

Moreau J; Moreau I, 1982. [English title not available]. (Etude de la gamétogenèse chez Heterotis niloticus au Lac Ivakoina (Zones des Pangalanes) Madagascar.) Revue d'Hydrobiologie Tropicale, 15(3):271-280.

Nelson GJ, 1968. Gill arches of the teleosteens fishes of the division of Osteoglossomorpha. Journal of the Linnean Society of London, Zoology, 47:261-277.

Nelson GJ, 1969. Infraorbital bones and their bearing on the phylogeny and geography of osteoglossomorph fishes. American Museum Novitates, 2394:1-37.

Nguenga D; Brummett R, 2003. [English title not available]. (Introduction du "Kanga" Heterotis niloticus (Cuvier, 1829) dans le fleuve Nyong (Cameroun): Echec ou réussite?.) In: International Conference of the Panafrican Fish and Fisheries Association, Cotonou, Benin, 10-14 November 2003.

N'Vogo L, 1962. Elevage de l'Heterotis niloticus dans les stations de pisciculture du Cameroun oriental ([English title not available]). Nogent-sur-Marne, France: Centre Technique Forestier Tropical.

Offem BO; Bassey I; Ikpi GU, 2011. Downstream Changes on a Tropical Fish Community Structure by Effluent from Wood Processing Factory. Journal of Environmental Protection, 2:982-995.

Olanyan CIO; Zwilling KK, 1963. The suitability of Heterotis niloticus (Ehrenberg) as a fish for cultivation with a note on their spawning behaviour. Bulletin de l'Institut Français d'Afrique Noire Noire (A Sci. Nat.), 252(2):513-25.

Olaosebikan BD; Raji A, 2005. Field guide to Nigerian freshwater fishes. Second Edition. New Bussa, Nigeria: Federal College of Freshwater Fisheries Technology, 106 pp.

Paperna I, 1996. Parasites, Infections and Diseases of Fishes in Africa - an Update. Technical Paper 31, Central Institute of Freshwater Aquaculture. Rome, Italy: Food and Agriculture Organization, United Nations.

Paugy D, 1990. Osteoglossidae. In: Lévêque C, Paugy D, Teugels GG, eds. Faune des poissons d’eaux douces et saumâtres de l’Afrique de l’Ouest. Tome 1. Coll. Faune Trop. n°XXVIII. Musée Royal de l’Afrique Centrale, Tervuren and Éditions de l’ORSTOM, Paris, 114-115.

Paugy D; Traoré K; Diouf PS, 1994. Faune ichtyologique des eaux douces d’Afrique de l’Ouest. In: Teugels GG, Guégan JF, Albaret JJ, eds. Biological diversity of African fresh- and brackish water fishes. Geographical overviews presented at the PARADI Symposium, Senegal, 15-20 November 1993. Ann. Mus. R. Afr. Centr., Sci. Zool., 275:35-66.

Pillay TVR, 1967. Proceedings of the FAO world symposium on warm-water pond fish culture, Rome, Italy, 18-25 May 1966. Volume 3. Review and experience papers of meetings 2 and 3. [FAO Fish Report 44.]

Rakotomanampisson A, 1966. Premiers résultats de l'acclimatation de Heterotis niloticus à Madagascar ([English title not available]). Tananarive, Madagascar: Direction des forêts, 32 pp.

Reed W, 1967. Fish and fisheries of northern Nigeria. Ministry of Agriculture Northern Nigeria, 226 pp.

Reizer C, 1964. [English title not available]. (Comportement et Reproduction de Heterotis niloticus en petits étangs.) Bois et Forêts des Tropiques, 95:49-60.

Reizer C, 1968. [English title not available]. (Influence et distribution de la nourriture artificielle sur la mortalité des alevins, la croissance préadulte, et la maturité sexuelle chez Heterotis niloticus.) FAO Fish Report, 44(3):326-58.

Rose KR; Cowan JH; Winemiller KO; Myers Hilborn RAR, 2001. Compensatory density-dependence in fish populations: importance, controversy, understanding, and prognosis. Fish and Fisheries, 2:293-327.

Scott DBC, 1974. The reproductive cycle of Mormyrus kannume Forsk. (Osteoglossomorpha, Mormyriformes) in Lake Victoria, Uganda. Journal of Fish Biology, 6:447-54.

Scott DBC; Fuller DJ, 1976. The reproductive biology of Scleropages formosus (Müller & Schleger) (Osteoglossomorpha, Osteoglossidae) in Malaya and the morphology of its pituitary gland. Journal of Fish Biology, 8:45-53.

Stiassny MLJ; Raminosoa N, 1994. The fishes of the inland waters of Madagascar. In: Teugels GG, Guégan JF, Albaret JJ, eds. Biological diversity of African fresh- and brackish water fishes. Geographical overviews presented at the PARADI Symposium, Senegal, 15-20 November 1993. Ann. Mus. R. Afr. Centr., Sci. Zool., 275:133-148.

Taverne L, 1979. [English title not available]. (Otéologie, phylogenèse et systématique des téléostéens fossiles et actuels du superordre des ostéoglossomorphes. Troisième partie.) Mém.CL. Sci., Acad.R.Belg, 43(3):1-168.

Teugels GG; Lévêque C; Paugy D; Traoré K, 1988. État des connaissances sur la faune ichtyologique des bassins côtiers de Côte d’Ivoire et de l’ouest du Ghana. Rev. Hydrobiol. Trop., 21(3):221-237.

Tillon R, 1957. Premiers résultats sur le comportement d'Heterotis niloticus en station de pisciculture ([English title not available]). Nogent-sur-Marne, France: Centre Technique Forestier Tropical, 6 pp.

Tillon R, 1959. [English title not available]. (Elevage de L'Heterotis niloticus en station de pisciculture.) Revue Bois et Forêts des Tropiques, 64:13-18.

Vincke M, 1971. Recherche sur Heterotis niloticus à la station de du Périnet ([English title not available]). Tananarive, Madagascar: Centre Technique Forestier Tropical, 18 pp.

Welcomme RL, 1975. [English title not available]. (L'écologie des pêches dans les plaines inondables de plaines inondables africaines.) Document Technique du CPCA, 3:1-51.

Welcomme RL, 1979. Fisheries ecology of floodplain rivers. New York, USA: Longman, 317 pp.

Welcomme RL, 1988. International introductions of inland aquatic species. FAO Fisheries Technical Paper, No. 294:x + 318 pp.

Welcomme RL, 2001. Inland fisheries: ecology and management. London, UK: Blackwell.

Winemiller KO; Rose KA, 1992. Patterns of life-history diversification in North American fishes: implications for population regulation. Canadian Journal of Fisheries and Aquatic Sciences, 49:2196-2218.

Winkle Wvan; Rose KA; Winemiller KO; DeAngelis DL; Christensen SW; Otto R; Shuter BJ, 1993. Linking life history theory, environmental setting, and individual-based modeling to compare responses of different fish species to environmental change. Transactions of the American Fisheries Society, 122:459-466.

Yao K; Yapo A; N'da K; Aoussi S, 2003. [English title not available]. (Effet de la densité d'élevage sur la croissance et la survie de Heterotis niloticus (Osteoglossidae) en captivité étroite.) In: International Conference of the Panafrican Fish and Fisheries Association, Cotonou, Benin, 10-14 November 2003.

Links to Websites

Top of page
GISD/IASPMR: Invasive Alien Species Pathway Management Resource and DAISIE European Invasive Alien Species Gateway source for updated system data added to species habitat list.
Global register of Introduced and Invasive species (GRIIS) source for updated system data added to species habitat list.


Top of page

Benin: PRECOB Programme de Recherches pour la conservation de la Biodiversité, Département de Zoologie et Génétique Faculté des Sciences et Techniques Université d’Abomey-Calavi, 08 BP 0234 Cotonou


Top of page

Date: 22/5/2012 

Original text by: Alphonse Adite, Département de Zoologie et Génétique, Université d’Abomey-Calavi, Cotonou, Benin

Reviewers' names are available on request.

Distribution Maps

Top of page
You can pan and zoom the map
Save map