is the month of October 2018 and the topic is a small
member of the Loricariidae family and one of the most
stunning discoveries of the last 14 years namely the
"Green Oto" Hisonotus aky. This
fish caused quite a stir in the hobby when first described
and all these years later it has now been bred in
Casciotta, Almirón & Körber, 2004)
was originally described in Epactionotus
Reis & Schaefer, 1998 because of its supposed
possession of three synapomorphies proposed for that
genus: neural spine of seventh vertebra not contacting
nuchal plate dorsally (contacting unpaired predorsal
plates), first dorsal proximal radial contacting the
eighth vertebral centrum, and absence of an expanded
fleshy flap on the dorsal surface of the first pelvic-fin
ray in males. Also, Hisonotus aky possesses
one of the additional diagnostic characters of Epactionotus:
longitudinal light stripes on dorsal surface of head.
However, the examination of type specimens of Epactionotus
aky indicates the absence of most diagnostic
features for the genus.
- three day old fry
This species has
been bred by English aquarist Paul Dixon from the
Bolton Museum, England and is shown above.
According to Evers
et al, they are only found in a small area
in the Rio Uruguay drainage in the Fortaleza Creek,
close to the city of Paraiso.
A very unique
species, in that it can be easily recognised by its
overall green body colour, although freshly imported
specimens are often olive coloured and do not show
the bright metallic green colouring until well settled.
South America:Argentina, Yabotí-Guazú basin,
Uruguay River system, Misiones. Type locality:
Argentina, Misiones, Río Uruguay basin, Arroyo
Garibaldi (26º38'46.1"S, 53º59'55"W).
The following summary is from
AZPELLICUETA et al (2004). Epactionotus
(Hisonotus) aky is diagnosed by the following
combination of characters: 1) 21 to 23 lateral plates;
2) light stripes extended from snout tip to supraoccipital
level; 3) caudal fin with dark vertical stripes; 4)
ventral surface of body completely covered by small
platelets; 5) 1-4 feeble serrae on distal portion
of pectoral spine posterior margin.
Green body colouration
although freshly imported specimens are often olive
coloured and do not show the bright metallic green
colouring until well settled.
Care & Compatibility
Peaceful fish with other companions
who like water movement in the aquaria.They rest on
aquatic vegetation in the aquarium and the less light
in the tank the darker they become. Provide a current
in your tank for this species as they come from swift
flowing waters. A sandy substrate is best with smooth
rocks and pieces of bogwood, with thickets of broad-leaved
plants such as Amazon swords.
They lay their
eggs on plant leaves.
Females grow a bit larger than
the males. The males usually are not as strong in colouration
and have longer fins.
Will feed on flake, algae,
tablet foods, algae wafers and insect based foods.
fin: The tail. Dorsal: The primary rayed fin(s) on
top of the body. Lateral:A sensory line, along the sides of the body. Nuchal: Area between the skull and
dorsal fin. Pectorals: The paired fins just behind
the head. Pelvic fins: The paired fins, between
the pectorals and the anal fins. (also referred to as
ventrals). Supraoccipital: Unpaired bone at the
back of the skull, usually with a crest.
Casciotta, Almiron, & S. Korber, 2004,
A new species of Otothyrini (Siluriformes: Loricariidae:
Hypoptopomatinae) from the Río Uruguay basin,
Evers, H.-G. & I.Seidel: Mergus, Baensch
Catfish Atlas Volume 1, 1st English edn., 2005. Pp.944. Ferraris, C.J. Jr., 2007. Checklist
of catfishes, recent and fossil (Osteichthyes: Siluriformes),
and catalogue of siluriform primary types. Zootaxa 1418:1-628. Fuller, Ian.
www.practicalfishkeeping.co.uk Tiago Pinto Carvalho; The species of
Hisonotus (Siluriformes: Loricariidae: Hypoptopomatinae)
of the Rio Uruguay basin, southeastern South America
in: A new species of Hisonotus (Siluriformes: Loricariidae:
Hypoptopomatinae) from the Laguna dos Patos Basin, Southern