Brown (1) Felipe
Sebastián Preisz (1)Enzo Edgardo Ferreyra (1)
Otocinclus arnoldi inhabits clear waters
of the southern regions of South America so this should
be taken into account with temperature values in the
home aquarium. Lives in the same waters as Corydoras
shares the same colour pattern. A similar looking
darker species has been imported in the past from
Uruguay. Aquarium Care: Requires
cool waters in the aquarium as sustained high values
can be problematic for this species. A planted tank
is best as it is kind to plants but will keep the
algae at bay. Can be a bit territorial with other
fish but do well together in groups. Diet:
Algae eater, tablet foods, lettuce, flake and small
live and frozen foods. Etymology:
This species was described from “LaPlata”
based on a single aquarium specimen donated by J.
P. Arnold. Remarks:
The recent paper (2010) by Lehmann, P., F. Mayer and
R.E. Reis have resurrected Otocinclus arnoldi
from the La Plata basin from the synonymy of O.
flexilis Cope 1894from the Rio Jacuí,
Rio Grande do Sul in Brazil and is thus a species
in its own right based on three distinguishing features:
the possession of five branched pectoral-fin rays,
the larger number of enlarged odontodes on the tip
of the parieto-supraoccipital posterior process, and
having the prootic involved in the contact with the
hyomandibular articular condyle.
South America:Argentina: tributaries of the lower Río
Paraná drainage, lower and middle rio Uruguai,
and the Río de La Plata. Type locality:
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.