hat behavior could make a more sustainable impression with its
owner? A medium-sized catfish with attractive colour, a slim
streamlined shaped body, and a great appetite. Persistently
he chases off even large adult cichlids to grab any chunks of
food that is available.
is an agile and fearless fighter/chaser for the “predator
aquarium". In particular, the feeding time promises interesting
and exciting observations. Other times it usually rests and
then gives the observer the idea of a somewhat timid and pretty
catfish, but with this species the first impressions can be
The genus Aguarunichthys belongs
to the family of the "Antenna Catfishes" (Pimelodidae)
and includes, besides the sporadic imported A. torosus,
two other species which are rare even in nature and therefore
are not imported very often, A. inpai which at 42 centimeters
SL is the biggest species and A. tocantinsensis which
at nearly 32 centimeters SL is a bit smaller than A. torosus
whose SL in nature is specified at approximately 35 centimeters.
Based on a light background all three have a characteristic
fine pattern of black dots/points which vary in number and size
depending on the species.
Particularly striking is a light zone
which is a little upstream of the middle of the body and which
extends obliquely to the rear in the form of a strip from the
back approximately to the beginning of the pectoral and ventral
fins. Young specimens of A. torosus are more brightly
coloured, but like adults they already show the typical stippling/mottling.
The Latin "torosus" stands for muscular and describes
the species quite well.
Kept in favourable good conditions this
catfish seems to stay in good shape and does not seem to have
too many grams of fat on its body, and probably why it has gained
the German common name of "Stier-Antennenwels"
(Bull antenna catfish).
A near adult specimen with almost 35 centimetres
in total length resting on its favourite place.
torosus in profile - his three pairs of highly sensitive
barbels allow him excellent orientation
Characteristics of Aguarunichthys torosus
Aguarunichthys torosus (Stewart, 1986); „Aguarun“
= Indian tribe, which lives on both sides of the Peruvian-Ecuadorian
border; gr. ichthys = "fish", lat. torosus = "muscular".
South America (Rio Cenepa, Peru).
Maximum 38 cm – 40 cm total length in nature.
A little tricky only in the adaptation period, then keeping
is relative unproblematic in preferably large aquariums
around 24° C, a powerful filtration, weekly water change,
increased current and additional air flow. Does not dig
so background planting therefore is possible. Single keeping
because of its intraspecies/interspecies territorial behaviour,
however can be socialized well with cichlids. Predatory
way of living, so do not select other fish species that
are too small for sociality.
|Gender differences and re-production:
Extremely agile hunter with a good sense of smell which
soon takes the food from the hand of its keeper. Also feeds
on earthworms and fish fillets.
In form shape and patterning A. torosus
reminds us of another, one-third bigger growing catfish of South
America, namely Calophysus macropterus,
which is comparatively more common in the trade. Unlike the
former, A. torosus is spotted nearly to the lower side/bottom
of the abdomen, it also lacks almost all of the bluish coloration
which is especially characteristic for adult C. macropterus.
A. torosus looks similar to C.
macropterus (right) which however is more compact
and reaches a larger final length.
Aguarunichthys torosus is not
one of the fastest growing predatory catfish, although a specimen
of 10 cm in length is capable in doubling its body size in about
one year, after that however it needs another good two to three
years to reach its maximum total length in the aquarium which
is usually hardly more than 35 centimeters. Therefore A.
torosus, unlike many others bigger growing Pimelodidae,
can be kept well by many predatory catfish lovers.
Acquisition & Keeping Conditions
Aguarunichthys torosus is regarded as a delicate and
sensitive species, especially newly imported young specimens
of ten centimeters and smaller. Sometimes they can die after
a short time of a mysterious skin disease which you can barely
get under control with medication. Although they are much more
expensive it is best to acquire animals from a length of about
20 centimeters. These should also be kept some time in the care
of the dealer, so you can be quite certain that for the large
price of about 100 to 150 Euros you have long lasting pleasure
in your acquisition. If the catfish has been acclimatised to
his new home it’s keeping turns out to be not as particularly
difficult, if some fundamental indicators are respected.
With adult specimens you should not keep them in tanks smaller
than a two metre length and a minimum depth of 70 centimeters.
If the aquarium is too small the danger is greater that the
catfish will scare itself, for example with a sudden approximation
or handling in the aquarium. It can then start to abruptly dart
to the surface and even jump out of the water. The temperature
in the tank should be 23 to 26 degrees Celsius and the pH is
ideally located between 6 to 7. Weekly partial water change
is also recommended.
A good tip tip is according to their origin from a river, the
species needs a lot of oxygen, so the keeper should provide
for a stronger flow and additional ventilation/aeration, then
the fish will feel better and visibly demonstrates this in a
more active lifestyle.
Juveniles during the day like to withdraw completely into a
shelter, but if the catfish exceeds 20 centimetres it does not
need a shelter where it can hide completely. It will find a
still viewable place in a corner in the rear area of the aquarium
next to a large root or under a high solitaire plant and that
is sufficient for it. There it rests during the day, most of
Its urge to move around is significantly less than that of the
more active C. macropterus. However if you believe,
because of the reduced final length of A. torosus compared
to C. macropterus, to be able to fall back on a smaller
tank you will be soon taught a lesson after introducing this
catfish in the aquarium. Though the movements of C. macropterus
sometimes can be quite fast, A. torosus once it picks
up speed is striking in its motion sequences which is fast paced
and like lightening. When fed also during the day, otherwise
no later than the onset of darkness, this catfish leaves its
place immediately and is actively looking for food. Younger
specimens no longer stay in their hiding places and they begin
to roam widely in the tank.
species is not a digger so that planting is possible with robust
bigger growing plants. Aguarunichthys torosus is a
predatory catfish which likes devouring live food such as earth
worms, but it also eats frozen foods such as whole and unbroken
smelts, shrimp or mussel meat. After a short familiarization
phase it does not disdain from eating fish fillets. Juvenile
catfish can be accustomed early to compound and mixed feeds
such as tablets or pellets, adult specimens however take them
This species will gladly prey on smaller fish. Their
hunting behaviour is interesting, which I could observe well
after a feeding of a large number of young, only a few centimetres
large, Archocentrus nigrofasciatus. Thereby it became
clear how very quickly this predator catfish is able to lunge
out. Although the young cichlids felt safe in a protected corner
specially set up with roots and large stones, my 35 centimetres
in total length, nearly adult A. torosus, registered
them immediately, as his barbels slightly moving in their direction
told. Apparently he was only waiting for a switching off of
the aquarium lighting, and indeed, even with the room lights
switched on, he preyed on them. Firstly he scared the cichlids
by restless searching movements, after which they sought salvation
on a wild run. He surprised them by a sudden, rapid lunge, and
having had devoured seven cichlids the catfish went to his favourite
place near a larger root and stayed motionless all during the
at full throttle.
Skilled food thieves
Aguarunichthys torosus also likes to show his ability
in a completely other kind of hunting, namely when it comes
to snatching other predators food or prey. He demonstrates this
behaviour above all when he is getting a raw deal with feeding
and the associated fish, because of the size of the food offered
and the time needed to devour it completely. Then the hunting
instinct of the catfish awakes and he gets carried away with
ever more daring actions. He will even steal from adult Astronotus
ocellatus any morsel of food such as fish fillet, even
if it sticks out just a little bit out of their mouth. Persistently
A. torosus will pursues the cichlids and in doing so his
extraordinary agility benefits him. Every direction the beleaguered
cichlids will take he manages to keep almost direct body contact
and harass them further in turbulent movements until it provides
a way for him to pull the piece of food as quick as a flash
from the mouth, or at least tear or rip off a part of it. If
A. torosus has the opportunity to eat himself full,
the need and requirment which with many other predatory catfish
can be observed, namely to eat very next day again if the opportunity
arose, is low. With him two or three days may pass in which
he downright scorns further food. For adult specimens therefore
a feeding of twice a week is absolutely sufficient.
With conspecifics and other species A. torosus behaves
fairly territorial, although you can still keep together juvenile
catfish if the aquarium provides enough hiding places but with
adult animals this does not work normally. They are too much
of a loner, and their territories, which they claim against
other species are too large, and that usually includes the entire
tank. At best large public aquariums permit such a coexistence.
Opposite to other fish species the territory is not so much
pronounced. An adult Aguarunichthys only defines its
territory area about 30 centimeters around his usual place,
but this zone he then defends against much larger fish being
quite aggressive and resolute. Usually A. torosus in
the context of its defensive action succeeds to catch the intruders
by fast and agile movements on very exposed body areas like
the tail fin with its mouth and pinching them in repeated attacks
for so long until they take flight. The socialised fish will
soon have learned to keep well away from this territory and
so in sufficiently spacious tanks socialisation for example
with cichlids is possible. Even with larger cichlids the keeper
does not have to worry about the well being of his A. torosus
because he shows himself surprisingly assertive, especially
at night where he will he wander around the entire bottom of
the tank. The cichlids know that and will only remain in the
middle and upper water regions.
At this stage however it can come to
conflicts with other bottom oriented predator catfish. A.
torosus tries to impress mainly through bumping, so I could
not watch injuries caused from that, so usually my specimen,
which is socialised with several Pimelodus ornatus
and Exallodontus aguanai will strike out blows as fast
as lightning. They have become used to his attacks long ago
and they normally avoid them. So if you want to socialise A.
torosus with other predatory catfish one should fall back
on smaller, fast swimming, and especially agile species and
provide them with additional retreats if at all possible. One
should avoid keeping this species together with larger and territorial
species from the Pimelodidae or Pseudopimelodidae, otherwise
trouble will be inevitable. In addition the keeper should always
be aware of the fact that A. torosus is a predator
catfish and for him, too small a fish, and these are basically
all which have less than a third of his own body size, especially
over night, run the risk of being eaten.
A. torosus knows itself well enough to be able
win through in a community tank with cichlids and other
The behavior towards the keeper are clearly
different from C. macropterus that even after many
years remains a bit cautious. Although initially it lives very
withdrawn sometimes even adult specimens lose their shyness
and even take food from the hand. The high speed which they
show thereby is unusual for predatory catfish. Resting on the
ground my specimen has already, after a short time sniffing
the scents and the trace smell from the dipped fish-pieces,
takes a few lines on the ground restlessly and finally ascends
in searching movements. His two longest barbles in these moments
literally vibrate and making as good a location as possible,
he single mindedly moves to the surface of the water where the
fish pieces have been immersed. Swimming by then he pulls and
tears larger pieces abruptly, and if necessary with pressure,
and forces the chunks out of my fingers which then at once disappear
in the surprisingly wide open mouth. Finally the catfish submerges,
goes to his favourite place only for a moment and then returns
taking the next chunk out of my hand.
The following images shows these motions.
Tame to the hand A. torosus, which grabs the
the piece of fish fillet at first very quickly and then
completely snatches it away from the hand with a strong
My overall impressions of A. torosus is that it just
looks great. This catfish impresses with its elegance
of its body shape, markings and swimming movements. As a powerhouse
he knows to win through even in a predatory community. The experienced
lover of predator catfish will not be able to avoid this species
and should not be deterred by the relatively high price, if
he/she can find it on the list of catfish specialist retailers.