THE STEINHART AQUARIUM - Gulf of Guinea Science ...

110 A Docent Field Guide to the Species of the Steinhart Aquarium
Reproduction and Development: Like other
members of their family, they undertake
dramatic mass migrations associated with both
feeding and reproduction.
Mortality/Longevity: Eaten by some predatory
fishes, such as the peacock bass (Cichla
temensis), often found in the Flooded Amazon
exhibit. Life span: c. 4 years.
Banded Leporinus
Leporinus fasciatus (Anostomidae)
Headstanders
Distribution: South America: Amazon and
Tocantins River basins. Also Guyana.
Habitat: Rivers with sandy bottoms.
Appearance: Light tan with two distinct black
spots (one before the tail and another on the
flank). Length about 12 cm.
Diet: Small invertebrates, other fish, and
plants. Will eat scales of larger fish.
Reproduction and Development: Spawns in
open water above substrate. Doesn’t guard eggs.
Remarks: Leporinus (L =”rabbit”) relates to this
fish’s large protruding teeth The species is also
known to leap out of the water, so perhaps its
name has more than one reference point!
Like all members of its family, it very often
position itself head down in rocky crevices.
Golden Pencilfish
Nannostomus beckfordi (Lebiasinidae)
Pencilfishes
Distribution: Amazon River basin in Guyana,
Suriname, French Guiana and northern Brazil.
Habitat: Sluggish small rivers and swampy
areas.
Appearance: Max. size: 6.5 cm. Elongate
cylindrical body gives them their common
name. Dark horizontal band extends through
the midline from head to tail. The male is more
colorful than female. The anal fin of the male
has a curved posterior edge; the female’s fin
edge is straight
Diet: Small worms, crustaceans, insects.
Reproduction: Fertilized eggs hatch in 2–3
days; fry are free swimming 3–4 days later.
Readily reproduce in captivity.
Mortality/Longevity: Life span: 5 or more
years.
Remarks: A schooling fish.
Like many species of pencilfishes, has a duller
nocturnal pattern and coloration that helps
camouflage it from would-be predators while
it sleeps.
Blind Cave Fish
Astyanax mexicanus (Characidae)
Characins
Distribution: Texas, New Mexico, and eastern
and central Mexico.
Habitat: Freshwater pools within dark caves.
Appearance: Head is notable for the absence
of eyes. Young born with functioning eyes
which become completely enclosed in tissue
as fish grows. Lack of sight is compensated
by a highly developed lateral line that detects
vibrations and changes in the water. The fish is
without pigmentation and is plain pink with a
silver sheen. They live in schools and grow to
about 12 cm in length.
Diet: A keen sense of smell and electrolocation
aid in finding food. Blind cave fish are
omnivores and feed on animal and plant
remains that wash into the caves and on bat
droppings from cave ceilings. Much of their
time is spent searching for food; they are able
to store four times more energy as fat than their
surface-dwelling relatives, allowing them to
deal with irregular food supplies.
Reproduction and Development: Egg layers.
Life span is approximately ten years.
Remarks: Both sighted, non-cave dwelling and
blind cave forms of A. mexicanus exist. These
fish are popular subjects for scientists studying
evolution—did the cave fish lose their eyes
because the lack of light and predators in dark
caves selected against vision?
When lenses from sighted fish were
transplanted to blind cave fish, eyes began to
develop. This research may eventually prove
useful in treating blindness in humans.
Blind cave fish have chemoreceptors all over
the head.
Sweepline Brycon
Brycon melanopterus (Characidae)
Characins
Distribution: Amazon basin.
Habitat: Freshwater streams and Florida ivers.
Appearance: Length to over 30 cm, weight to
4.3 kg.