Actinopterygii (ray-finned fishes) > Gonorynchiformes
(Milkfish) > Kneriidae
Etymology: Grasseichthys: Greek, grassos, -ou = stink, dirt + Greek, ichthys = fish (Ref. 45335). More on author: Géry.
Environment: milieu / climate zone / depth range / distribution range
Freshwater; benthopelagic. Tropical
Africa: scattered localities in the Ivindo and the larger Ogowe basin of Gabon; reports from the central Congo basin refer to another species (Ref. 81636).
Size / Weight / Age
Maturity: Lm ?  range ? - ? cm
Max length : 2.1 cm SL male/unsexed; (Ref. 42473)
Morphology | Morphometrics
soft rays: 9 - 10;
Vertebrae: 35 - 36. Diagnosis: very small and larval in appearance; body elongate, laterally compressed, shallow (body depth 17.9-20.0% SL in females and 15.2-17.9% SL in males); scaleless; head small (head length 18.0-22.7% SL), with small, terminal mouth and large eyes; teeth absent; interorbital distance narrow (11.9-12.9% HL); gill opening short and located above pectoral fin; pectoral fins positioned ventrally and often splayed out from the body in preserved specimens; caudal peduncle long, with keels of transparent tissue, apparently anterior extensions of caudal fin membrane, reaching forward on both dorsal and ventral edge (ventral extension is more developed); caudal fin forked, with 16 rays, including an unbranched ray on dorsal and ventral edge; fin spines lacking; 2 branchiostegal rays; body semi-translucent, with myomeres clearly visible; lateral line absent; epibranchial organ reduced or absent (Ref. 81636).
Open water species, not burrying in sand; forms schools; spawns during the raining season, during which it may be very abundant, forming aggregations in open water areas in the swamps; females of 20-24mm carry about 40 round, ripe eggs of about 0.4mm diameter; males mature at a size of about 18mm total length (Ref. 91379).
Life cycle and mating behavior
Maturity | Reproduction | Spawning | Eggs | Fecundity | Larvae
Géry, J., 1965. Poissons du bassin de l'Ivindo. I - Les biotopes. Biol. Gabon. 1(4):375-384. (Ref. 91379)
IUCN Red List Status (Ref. 115185)
CITES (Ref. 115941)
Threat to humans
Common namesSynonymsMetabolismPredatorsEcotoxicologyReproductionMaturitySpawningFecundityEggsEgg development
ReferencesAquacultureAquaculture profileStrainsGeneticsAllele frequenciesHeritabilityDiseasesProcessingMass conversion
Estimates of some properties based on models
Phylogenetic diversity index (Ref. 82805
= 1.0000 [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), in cm Total Length, 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) .