Classification / Names
Common names | Synonyms | Catalog of Fishes(genus, species) | ITIS | CoL | WoRMS | Cloffa
Actinopteri (ray-finned fishes) > Characiformes
(Characins) > Characidae
(Characins; tetras) > Stevardiinae
Etymology: Knodus: Greek, knodon, -ontos = knife, sword (Ref. 45335); geryi: Named after Jacques Géry, in recognition of his enormous contribution to the knowledge of the characiform fishes.
Environment: milieu / climate zone / depth range / distribution range
Freshwater; benthopelagic. Tropical
South America: rio do Peixe in the upper rio Paraguay basin, Brazil.
Size / Weight / Age
Maturity: Lm ?  range ? - ? cm
Max length : 6.5 cm SL male/unsexed; (Ref. 55831)
Morphology | Morphometrics
soft rays: 18 - 20;
Vertebrae: 38 - 39. Differs from all congeners and from all remaining characid fishes by having two symmetric, large dark blotches basally on caudal fin lobes (Ref. 55831).
Inhabits small river with transparent waters, very channeled and relatively deep (> 2 m deep in some points), having both rapids and waterfalls (Ref. 55831). Feeds on vegetal matter and insects (Ref. 55831).
Life cycle and mating behavior
Maturity | Reproduction | Spawning | Eggs | Fecundity | Larvae
Lima, F.C.T., H.A. Britski and F.A. Machado, 2004. New Knodus (Ostariophysi: Characiformes: Characidae) from the upper Rio Paraguay basin, Brazil. Copeia 2004(3):577-582. (Ref. 55831)
IUCN Red List Status (Ref. 123251)
CITES (Ref. 123416)
Threat to humans
Common namesSynonymsMetabolismPredatorsEcotoxicologyReproductionMaturitySpawningSpawning aggregationFecundityEggsEgg development
ReferencesAquacultureAquaculture profileStrainsGeneticsAllele frequenciesHeritabilityDiseasesProcessingNutrientsMass conversion
Estimates based on models
Phylogenetic diversity index (Ref. 82805
= 0.5000 [Uniqueness, from 0.5 = low to 2.0 = high].
Bayesian length-weight: a=0.01047 (0.00549 - 0.01997), b=3.00 (2.83 - 3.17), in cm total length, based on LWR estimates for this species & (Sub)family-body (Ref. 93245
Trophic level (Ref. 69278
): 3.2 ±0.40 se; based on food items.
Vulnerability (Ref. 59153
): Low vulnerability (10 of 100) .