Catfish of the Month September 2002 • Article © Chris Ralph, uploaded September 01, 2002
Granulated Catfish, Armado (Venezuelan), Bacu (Brazilian), Common Bacu, Ru Tornmalle (Denmark) - Pterodoras granulosus (Valenciennes in Humboldt & Valenciennes, 1821)
This month sees another scoop in the catfish of the month
article section. Chris Ralph takes time out from answring catfish queries for
Practical Fishkeeping Magazine and judging catfish to write about this gentle
giant of the amazon waterways. Here is what he has to say:
The Common Bacu or Pterodoras granulosus is
another of my favourite large catfish, which I currently have the pleasure to
keep. At the moment I have three of these "gentle giants" housed within my 12'
x 3' x 4' tropical pond. They vary in size from approximately 600mm (24") to
900mm (36"). Two well-known "Catfish Fanatics" initially purchased all three
catfish at the same time in the South of England - Tony Tyson and Terry
Wilkins. I was asked to rescue one of these catfish from Terry as it had
outgrown its accommodation namely a 72" x 24" x 24" aquarium. At the time of
its transfer to my tropical pond it was approximately 20" total length, some
two and half years later this fish is closer to 36" total length. This catfish
was given the name "Well Ard" and the name has stuck. (For our international
audience I should point out that "Well Ard" alludes to the fishes hardy nigh on
indestructible nature - Ed). I quite often get people asking me how Well Ard is
doing. I purchased the other two catfish from Tony and introduced them to the
pond a couple of months later when they were approximately 6" in length. These
two fish are now approximately 24" long and are eating anything that is offered
to them including catfish pellets, floating food sticks, pond pellets, whole
prawns, mussels, cockles and earthworms.
My observations of these fish suggest that I might have
two females and one male, as I have two rather fat catfish and one, which is
more slender. I have not seen any obvious signs of spawning activity to date,
but these catfish are quite happy to swim around the pond together. Of the
three catfish Well Ard is perhaps the tamest of the three allowing me to feed
her by hand! These catfish are kept in with a number of other large catfish
including Pseudodoras niger, Megalodoras uranoscopus, Leiarius
pictus, Auchenoglanis occidentalis and numerous Synodontis
species. Due to the size that these catfish can attain keeping them in anything
smaller than a 72" x 24" x 24" aquarium should not be considered, and it should
be pointed out that even this size aquarium is really a little too small!
Whilst fish collecting in Peru two years ago with a
number of members of the Catfish Study Group (UK) including Jools & Clare
Dignall, Allan James, Giles Barlow, Robin Warne, Steve Pritchard, Terry Wilkins
and Alan Appleton, we caught a couple of these catfish on rod and line. They
were to spend the next few days on board our accommodation for the week, only
to be returned to the point at which they were caught originally. I decided
that the three specimens that I had at home already were enough and that they
would be better off swimming in the Amazon! In South America the local
inhabitants would catch and eat these catfish, and as you can imagine a large
specimen would feed a whole family for a few days. Seeing these catfish in
their natural habitat was an amazing experience, one that will live with me for
a long time to come.
The common bacu are found throughout the river systems
of South America. The colour pattern of these catfish varies depending upon the
location that they originate from. These fish are usually a muddy-brown colour
with some darker spots over the body and fins. As these fish mature the
spotting tends to fade. Juvenile specimens tend not to be as dark coloured as
adult fish, in fact the two specimens caught in Peru were light brown/tan in
colouration. The body of these catfish is best described as being robust. The
body is naked i.e. it is devoid of scales, but the skin is very thick and
tough. There are between 23 and 28 shallow lateral plates known as scutes along
the length of the body. Their eyes are very small in comparison to the rest of
the fish and they have three simple pairs of barbels. They have a deeply forked
caudal fin, which also helps to distinguish this fish from other large
Doradids. In their natural habitats these catfish are migratory, shoaling in
large numbers as they make their journeys upstream to spawn.
Copyright information for the images used in this article can be found on the species' full Cat-eLog page.
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