THE STEINHART AQUARIUM - Gulf of Guinea Science ...

Diet: Insects and decaying fruits and vegetation
that fall into the water. (Do these fish celebrate
the inevitable last flight of a bola butterfly?)
Reproduction and Development: Fertilization
external, one seasonal spawning peak per
year. Open water/substratum egg scatterers.
Nonguarders.
Mortality/Longevity: Known to live to 28
years.
Remarks: Because pacu are closely related to
piranha, sharing their coloration and shape,
Hollywood producers have been known to
use the pacu as a stand-in for piranha. Actors
are appreciative of the pacu’s preference for
vegetable matter.
Like the tambaqui, an important aquacultured
food fish in South America.
Red-bellied Piranha
Pygocentrus nattereri (Characidae)
Characins
Distribution: Amazon, Paraguay-Paraná and
Essequibo basins.
Habitat: Freshwater creeks and interconnected
pools.
Appearance: Length to 33 cm. Weight to 3.8 kg.
Laterally compressed. Primarily dark scales with
silvery glitter highlights. Chin and belly reddish.
Diet: Prey primarily on wounded and diseased
fish. Feed communally in groups of 20–30 individuals
who wait in vegetation for the opportunity
to ambush prey. Once prey is attacked
a feeding frenzy ensues. Adults forage at dusk
and dawn, medium-sized fish most active at
dawn, late afternoon and at night; small fish
feed by day. Also scavenge on waste dumped
into rivers from slaughterhouses. Former CAS
Steinhart Aquarium director Earl Herald used
to feed piranhas the hearts of horses!
Reproduction: Spawn after an elaborate
courtship ritual where the mating pair swims
in circles. Female deposits layers of eggs on
aquatic plants; male fertilizes. Male defends
and turns eggs. Masses hatch in 9–10 days.
Mortality/Longevity: Preyed upon by other
fishes including large catfishes, crocodilians,
birds and larger mammals including jaguar.
Remarks: The piranha’s reputation as a voraciously
attacking humans is highly exaggerated.
The red-bellied piranha is primarily a
scavenger. Stories of cows and humans striped
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clean of flesh may be true, but the “meal” in
question was not alive when the attack took
place.
Even so, piranha’s can inflict a serious wound.
Jaw muscles are incredibly strong, and the
razor-sharp teeth on top and bottom fit in
an interlocking pattern. These two features
make the red-bellied piranha an efficient and
formidable feeder.
Of the 20 or so species of piranha, 12 do not
attack in schools. Rather they take a quick bites
of the fins or scales of passing fish, causing little
damage as these parts grow back.
Amazonian Indians use the sharp teeth as
knives. They also coat the teeth with curare and
attach them to the end of blow darts.
ORDER SILURIFORMES
(CATFISHES)
Channel Catfish
Ictalurus punctatus (Ictaluridae)
North American Freshwater Catfishes
Distribution: North America: Central
drainages of the United States to southern
Canada and northern Mexico.
Habitat: Rivers and streams, ponds and
reservoirs, especially on sand or gravel bottom
near rocks or logs where they hide during the
day.
Appearance: Color varies from blue, black,
olive; speckled above, lighter below, with
males generally darker than females. Like all
catfish, are scaleless. Two barbels in upper jaw,
and four below. Max. length: 130 cm; common
length: 60 cm.
Diet: Opportunistic omnivores. Active at
night, in search of fishes such as yellow perch
and sunfish. Also snails, algae, snakes, frogs,
insects, aquatic plants, and an occasional bird
or small mammal.
Reproduction and Development: The channel
catfish is monogamous at least for a single
mating season and displays a complex
courtship behavior. Mating takes place in the
summer. The male and female wrap their tails
around each other’s head; when the male
shivers, the female is stimulated and eggs
and milt are released. Eggs are laid in a nest
prepared by the male or both parents, often
under overhangs or in deep holes. The male