Classification / Names
Common names | Synonyms | Catalog of Fishes (gen., sp.) | ITIS | CoL | WoRMS | Cloffa
Actinopterygii (ray-finned fishes) > Characiformes
(Characins) > Characidae
(Characins) > Incertae sedis
Etymology: Hemigrammus: Greek, hemi = half + Greek, gramma = letter, signal (Ref. 45335); diagonicus: Name from Latin diagonicus, meaning diagonal, referring to the position of the blotch on the caudal fin, unique among the species of Hemigrammus.
Environment: milieu / climate zone / depth range / distribution range
Freshwater; benthopelagic. Tropical; 2°S - 3°S, 55°W - 57°W
South America: Brazil.
Size / Weight / Age
Maturity: Lm ?  range ? - ? cm
Max length : 2.8 cm SL male/unsexed; (Ref. 87304)
Morphology | Morphometrics
Hemigrammus diagonicus can be easily differentiated from its congeners, except for Hemigrammus silimoni, by the presence of a blotch on the caudal fin restricted to the dorsal lobe (vs. no blotches on the caudal fin, blotches restricted to the base of the rays, or blotches arranged symmetrically in dorsal and ventral lobes). Hemigrammus diagonicus is distinguished from H. silimoni by the autapomorphic presence of the caudal-fin blotch shaped like a bar that extends diagonally from the base of the median rays to the end of the upper lobe rays (vs. conspicuous ocellus like blotch on the lower region of the caudal-fin dorsal lobe); height of dorsal fin 22.3–30.2% SL (vs. 31.0–37.4% SL); length of anal-fin base 24.0–28.0% SL (vs. 28.7–31.5% SL); horizontal eye diameter 33.8–41.3% HL (vs. 43.4– 48.1% HL) (Ref. 87304).
Life cycle and mating behavior
Maturity | Reproduction | Spawning | Eggs | Fecundity | Larvae
Mendonça, M.B. and W.B. Wosiacki, 2011. A new species of Hemigrammus from the Lower Amazon Floodplain (Characiformes: Characidae). Copeia 2011(2):211-215. (Ref. 87304)
IUCN Red List Status (Ref. 120744)
CITES (Ref. 118484)
Threat to humans
Common namesSynonymsMetabolismPredatorsEcotoxicologyReproductionMaturitySpawningSpawning aggregationFecundityEggsEgg development
ReferencesAquacultureAquaculture profileStrainsGeneticsAllele frequenciesHeritabilityDiseasesProcessingMass 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=0.01318 (0.00593 - 0.02930), b=3.08 (2.89 - 3.27), in cm Total Length, based on LWR estimates for this (Sub)family-body shape (Ref. 93245
Trophic Level (Ref. 69278
): 3.0 ±0.4 se; Based on size and trophs of closest relatives
Resilience (Ref. 120179
): High, minimum population doubling time less than 15 months ().
Vulnerability (Ref. 59153
): Low vulnerability (10 of 100) .