Classification / Names
Common names | Synonyms | Catalog of Fishes(genus, species) | ITIS | CoL | WoRMS | Cloffa
Teleostei (teleosts) >
Siluriformes (Catfishes) >
Loricariidae (Armored catfishes) > Hypoptopomatinae
Etymology: Otocinclus: Greek, ous, oto = ear + Latin, cinclus = latticework; in allusion to the holes of the head in the ears (Ref. 45335).
Eponymy: Johann Paul Arnold (1869–1952) was a German aquarist in Hamburg. He sent specimens to Boulenger for study and identification. He co-wrote: The alien freshwater fish (1936). (Ref. 128868), visit book page.
More on author: Regan.
Environment: milieu / climate zone / depth range / distribution range
Ecology
Freshwater; demersal. Subtropical
South America: lower río Paraná drainage, lower and middle rio Uruguai, and río de La Plata.
Size / Weight / Age
Maturity: Lm ? range ? - ? cm
Max length : 4.8 cm SL male/unsexed; (Ref. 86395)
Short description
Identification keys | Morphology | Morphometrics
Distinguished from all congeners species except Otocinclus mimulus, by having five pectoral branched rays (vs. six pectoral branched rays), and except from Otocinclus mimulus and Otocinclus xakriaba by having the prootic involved in the contact with the hyomandibular articular condyle (vs. only compound pterotic contacting the hyomandibular articular condyle). Differs from Otocinclus mimulus by having a not elevated patch of enlarged odontodes on the postero-dorsal parietosupraoccipital tip and 15 caudal vertebrae (vs. having an elevated patch of enlarged odontodes on the parietosupraoccipital and typically having 16-17 caudal vertebrae). Can be further distinguished (except for Otocinclus affinis, Otocinclus hasemani, Otocinclus xakriaba, Otocinclus mimulus and Otocinclus flexilis) by possessing an iris operculum, and from Otocinclus affinis, Otocinclus mimulus and Otocinclus xakriaba by having a not elevated patch of enlarged odontodes on the postero-dorsal parieto-supraoccipital tip. Differs also from all remaining congeners (except for
Otocinclus xakriaba, Otocinclus flexilis, and Otocinclus mimulus) by having a lateral trunk coloration composed of either a row of 3-6 distinct dark blotches or a distinct dark stripe extending from the compound pterotic to the base of the caudal fin, or a diffuse mixture of those two color patterns (Ref. 86395).
Facultative air-breathing in the genus (Ref. 126274)
Life cycle and mating behavior
Maturity | Reproduction | Spawning | Eggs | Fecundity | Larvae
Lehmann, A.P., F. Mayer and R.E. Reis, 2010. Re-validation of Otocinclus arnoldi Regan and reappraisal of Otocinclus phylogeny (Siluriformes: Loricariidae). Neotrop. Ichthyol. 8(1):57-68. (Ref. 86395)
IUCN Red List Status (Ref. 130435: Version 2024-2)
Threat to humans
Harmless
Human uses
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Internet sources
Estimates based on models
Phylogenetic diversity index (Ref.
82804): PD
50 = 0.5000 [Uniqueness, from 0.5 = low to 2.0 = high].
Bayesian length-weight: a=0.00851 (0.00374 - 0.01935), b=3.09 (2.90 - 3.28), in cm total length, based on LWR estimates for this (Sub)family-body shape (Ref.
93245).
Resilience (Ref.
120179): High, minimum population doubling time less than 15 months (Preliminary K or Fecundity.).
Fishing Vulnerability (Ref.
59153): Low vulnerability (10 of 100).
