Actinopterygii (ray-finned fishes) > Gonorynchiformes
(Milkfish) > Kneriidae
Etymology: Cromeria: Perhaps related to the prehistoric Stone Age in eastern England; for the stone implements found in Cromer but needs more data.
Environment / Climate / Range
Freshwater; benthopelagic; pH range: 6.2 - 7.5. Tropical; 25°C - 30°C (Ref. 91322), preferred ?
Africa: basins of upper and middle Niger River, Benoué and upper Volta in Guinea, Mali, Burkina Faso, Ghana, Benin, Cameroon (Ref. 57474), Chad (Ref. 367) and Ivory Coast (Ref. 3066). Probably also in Togo, Nigeria and Niger (Ref. 57474).
Size / Weight / Age
Maturity: Lm ?  range ? - ? cm
Max length : 4.4 cm SL male/unsexed; (Ref. 91321)
Morphology | Morphometrics
soft rays: 7 - 8;
Vertebrae: 40 - 43. Diagnosis: pelvic fin origin at level of anterior base of dorsal fin; preorbital stripe present; caudal peduncle depth 6.9-11% of SL; dorsal precaudal fin fold not reaching base of dorsal fin; 8-9 pectoral fin rays; 7 pelvic fin rays; 2 supernumerary rays in anal fin; 8 dorsal fin pterygiophores; 9+9 principal caudal fin rays; cephalic lateral line canals and supraorbital bone present; parasphenoid wide, with foramina for internal carotid arteries; neural spine of 2nd vertebra short and wide, only the length of its vertebral centrum and different from subsequent neural spines (Ref. 57474).
Maximum TL was recorded at 4.1 cm (Ref. 3566). Occurs on several substrates from fine mud to rough gravel and plant material; almost never buries into the substrate (Ref. 57474). Feeds on plankton (Ref. 57474, 91322) and phytoplankton (Ref. 91322). Reproduction likely takes place during the rainy season (August to September) (Ref. 57474) at high water levels in floodplains, brooks or rice fields (Ref. 91276, 91322).
Life cycle and mating behavior
Maturity | Reproduction | Spawning | Eggs | Fecundity | Larvae
Moritz, T., R. Britz and K.E. Linsenmair, 2006. Cromeria nilotica and C. occidentalis, two valid species of the African freshwater fish family Kneriidae (Teleostei: Gonorhynchiformes). Ichthyol. Explor. Freshwat. 17(1):65-72. (Ref. 57474)
IUCN Red List Status (Ref. 109396)
CITES (Ref. 94142)
Threat to humans
Common namesSynonymsMetabolismPredatorsEcotoxicologyReproductionMaturitySpawningFecundityEggsEgg development
ReferencesAquacultureAquaculture profileStrainsGeneticsAllele frequenciesHeritabilityDiseasesProcessingMass conversion
Estimates of some properties based on models
Phylogenetic diversity index (Ref. 82805
= 0.7500 [Uniqueness, from 0.5 = low to 2.0 = high].
Bayesian length-weight: a=0.00389 (0.00180 - 0.00842), b=3.12 (2.94 - 3.30), based on all LWR estimates for this body shape (Ref. 93245
Resilience (Ref. 69278
): High, minimum population doubling time less than 15 months ().
Vulnerability (Ref. 59153
): Low vulnerability (10 of 100) .