H. platyrhynchos is easily recognized by its visible underbite, with the lower mandible of its jaws extending out farther than the upper mandible.
for aquarists, as the fish is such a dedicated
predator that it is often hard to acclimate it
to pellet foods. Regardless, there are many
acceptable options that can be offered for
H. platyrhynchos in the home aquarium.
For juvenile specimens, foods such as
bloodworms, brine shrimp, freeze-dried
tubifex worms, beef heart, mysid shrimp,
ghost shrimp, and leaf worms are acceptable.
For sub-adult and adult specimens, the size
of the food will have to increase, and the
implementation of foods such as cut fish
fillets, earthworms, and krill can be utilized.
H. platyrhynchos is less skittish than the
various Pseudoplatystoma species and can
be hand-fed even at a young age. Feeder
fish are also taken with gusto by specimens
of any size, and H. platyrhynchos can easily
consume a fish that is a third of its size. H.
platyrhynchos stalks its intended prey in a
slow, deliberate manner, and then furiously
lunges toward its victim once its antenna-like barbels have made contact. Rarely does
a meal that can fit inside of this catfish’s
mouth get away from its strong jaws.
In my opinion, though, the use of feeder
fish carries far too much of a risk of
infecting a prized specimen, for there is a
high possibility of transferring parasites
and disease into your tank from the feeders.
Also, most feeder fish have low nutritional
value, and it is far safer to feed the previously
mentioned foods. Basically, the only time I
feed any of my predatory fish live feeders
is if they are a finicky species that refuses
to eat all other types of food except for live
fish. Even when this is the case, I quarantine
feeder fish for at least two weeks and treat
with strong anti-parasite medication and
gut-load the feeders with veggie flakes
before giving them to my predators in order
to maximize nutritional value.
This brings up another important aspect
that should not be overlooked, which is
varying the diet of H. platyrhynchos. Feeding
only one type of food can lead to nutritional
deficiencies and poor health, so the
challenging aspect here is finding a way to
implement some type of vegetable matter into
its diet if your specimen will not accept pellet
foods. In the wild, H. platyrhynchos would
be consuming various fish and invertebrates
that are herbivorous, which provides a certain
degree of nutritional transfer. Gut-loading
feeder fish that have been treated for disease
could be an option, but there is a safer option
that can be utilized.
My close friend Alex, who breeds discus,
called me one afternoon and asked if I
wanted some of his homemade discus food
because he had made far too much. The
contents of the blend he created and froze
into sheets were cut fish fillets, market
shrimp, hardboiled egg yolk, spinach,
peas, crushed multivitamins, and garlic.
The frozen food sheets definitely had an
interesting smell when thawing prior to
feeding, but once added to my largest
display tank, enduring the smell was well
worth it: All of the inhabitants of the tank,
including my H. platyrhynchos, readily
consumed the homemade fish food. Maybe
it was the garlic or maybe it was the
fish fillets or shrimp, but either way, my
predatory catfish was enticed enough by
this concoction to eagerly receive green
matter in its diet.
A minimum tank size for an aquarist
to maintain H. platyrhynchos through
adulthood would be a standard 180-gallon
aquarium, which would measure 6 feet in
length, 2 feet in width, and 2 feet in height.
The length and width of the aquarium are
particularly important, as the 20- to 21-inch
adult must be able to turn comfortably
and have ample room to explore. The
longer the tank the better, as my 9-inch
H. platyrhynchos enjoys stretching his fins
at lights-out in my 240-gallon (8- x 2- x
2-foot) tank. He emerges from his cave and
swims back and forth the entire length of the
tank searching for food. Smaller specimens
can be maintained in smaller tanks, which
should be no less than 75 gallons, but the
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