of attaining. Additionally, Pseudoplatystoma
do not like changes, and if a small specimen
is constantly being bumped up from tank
to tank as it grows, there is a good chance
that stress will keep it from thriving and
thus shorten its lifespan.
Since Pseudoplatystoma generally grow
to at least 3 feet in length, it should be
said that no aquarium with a footprint less
than 10 x 6 feet be considered for the long-term keeping of such beasts. In most cases
height is not a factor, since large aquariums
are usually quite deep in comparison to
standard ones. Unfortunately the likelihood
of finding such an aquarium at an affordable
cost to the average hobbyist is poor, so if
procuring and accommodating a tank of
this size is not within your means, it would
be better to re-think the idea of adding one
of these creatures to your fish collection.
Feeding and Growth
It should not come as a surprise that
Pseudoplatystoma are carnivorous catfishes.
Essentially, any meaty fare that is capable
of being swallowed whole is considered a
potential food item. In nature, the bulk of
their diet consists of fishes and crabs. In
aquaria a diet of whole or cut (dead) fish,
such as smelt, is standard fare. Other foods
should be offered, however. Suitable items
include: shrimp, clam, mussel, squid, and
large sinking pelleted feed. Additionally,
large earthworms make for an outstanding
addition to their dietary regimen and should
be offered regularly.
The use of live fishes as feeders is common
practice with large predatory species like
those in the genus Pseudoplatystoma.
Many keepers use them without problems.
However, with the use of live feeder fishes
comes the heightened risk of disease
transmission from the feeders to the
display fishes. In most cases the diseases
most commonly transmitted are external
parasitic ones, like ich for example. While
most of the parasites are easily cured using
one of the many commercial remedies
on the market, catfishes are usually quite
sensitive to these treatments, and they
often succumb to a parasitic infestation that
would normally be nothing but a nuisance
to most other fishes. Just something to
keep in mind when offering live feeder
fishes to your prized catfishes.
The water conditions of aquariums
containing Pseudoplatystoma should
Tiger shovelnose catfish Pseudoplatystoma sp.
be excellent. Nitrogen compounds (i.e.,
ammonia, nitrite, nitrate) should be as close
to zero as possible. The temperature should
be in the area of 78°F or slightly cooler.
Keep in mind that even though these are
tropical fishes, they often occur in areas
of high current and deep water, where the
temperature will surely be several degrees
cooler than the temperature of the surface
layer (above the thermocline).
In order to keep excellent water quality in
aquariums containing these large predatory
catfishes, you must perform large water
changes on a regular basis. In most cases
a water change of anything less than 50
percent is useless. As a matter of fact, such
large water changes are in order for all large
predatory fishes, not just Pseudoplatystoma.
Of course it is imperative that rapid
changes be avoided, especially since many
species of catfishes do not take to rapid or
significant changes in water chemistry well.
By performing regular large-scale water
changes on a weekly or bi-weekly schedule,
you can reduce the likelihood that such
wide shifts in water quality become a
problem, since the buildup of pollutants
will never be an issue.
Tankmates for these large-growing
predatory catfishes should be selected
carefully. Fishes that are easily spooked
or jumpy in nature should be avoided,
since the nighttime forays by the catfish
will undoubtedly frighten them, perhaps
enough to actually have the scared fish leap
out of the aquarium.
Fishes that tend to pick on the fins
or barbels of other fishes should also
be avoided. Pseudoplatystoma have large
barbels that extend quite a distance from
their snout. Often while the fish is resting
these barbels are extended outward,
providing a sensory shield around the
head of the catfish. The water current will
make the tips of these barbels sway back
and forth, thus causing the extensions to
become a thing of interest to fishes that may
end up picking at them. P. fasciatum seems
to be particularly annoyed by repeated
assaults on their barbels, and after only a
short time they may become restless and
constantly stressed from this situation,
which invariably ends with the catfish
succumbing to a stress-related illness.
A few of the more commonly used
tankmates for Pseudoplatystoma species
are Colossoma pacu, river stingrays
Potamotrygon, Astronotus oscars, peacock
basses Cichla, and other species of large
catfishes from various genera.
Currently there are three recognized
species within Pseudoplatystoma, all of
which look very similar in appearance—
especially as juveniles. In most cases,
specimens sold as P. fasciatum are actually P.
tigrinum, although many are farm bred and
appear to have been hybridized sometime in
the past, as young tend to show phenotypic
traits of both species.
(SPIX & AGASSIZ 1829)
Growing to about 65 inches (166 cm)
in total length, the spotted shovelnose