Desirable attributes of
species used in small
scale aquaculture
- Protocol

Species commonly used
for aquaculture in
sub-Saharan Africa:
-O. andersonii
-O. aureus
-O. macrochir
-O. mossambicus
-O. niloticus
-O. shiranus
-Tilipia rendalli
-T. zillii
-Clarias gariepinus
-Cyprinus carpio
-Chrysicthys nigrodigitatus
-Heterotis niloticus
-Production of all-male
cichlid offspring

Alien species in African aquaculture
-Enviromental and economic
impacts
-FAO Codes of Practice

Heterotis niloticus (fantang, remej)

Family: Osteoglossidae

Size: Adults attain approximately 85 cm TL.

Native range: The Nile, Senegal, Gambia & Niger Rivers. Also Lake Rudolf & Lake Chad.

Habitat preference & tolerance levels: Generalised habitat requirements. Found in swamps, weedy areas of rivers and shallow well-vegetated lakes. Also in flowing channels and floodplains (grasslands) and in brackish water in estuaries. Tolerates very low limits of DO. Swim bladder modified to form suprabranchial organ, so can breathe atmospheric oxygen.

General biology and aquaculture potential: Omnivorous and microphagous species. Predominantly a bottom feeder. Young feed on zooplankton. Adults feed mostly on dipteran insect larvae (especially Chaeoborus sp. larvae) and copepods, supplemented with molluscs and higher plants. Also consume algae. Sub-adults and juveniles feed mostly on copepods. Diet varies with locality and season. Diurnal feeding rhythm, with most feeding taking place at dawn and dusk. Elaborate nests of 1 - 1.5 m diameter are constructed by clearing the bottom and building a wall of vegetation around the nest. Larvae initially have external gills which are lost after approximately 2-3 days. Juveniles remain in nest for approximately 5 days, after which they form a school which is guarded by parent. Produces many thousands of young i.e. is highhy fecund. Spawning is relatively easy but there are difficulties in ensuring good survival of young. Best to culture in small numbers (500 - 1000 large individuals only) in big ponds exceeding 2 ha or in large impoundments. Does well in polyculture with O. niloticus due to partitioning of resources. Fingerlings normally collected from natural waters - particularly coastal wetlands. 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.

Growth: Slow to mature and does not spawn until an age of 19 - 20 months. Growth rate in ponds is high, but declines if very densely stocked.

References: Boulenger 1907; Ezenwa & Ayinla 1994; Loiselle 1992; Micha 1974; Micha & Franke 1976; Ugwumba 1992.

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