158 Sharks: The Animal Answer Guide
■ Bamboo Sharks ($100): “Temperatures between 72 and 78 degrees Fahr-
enheit, pH of 8.1 or 8.4, specific gravity of 1.020 to 1.025.... Strong
shark can easy dislodge unstable rock formations and corals.... All
items in the tank should be stable.”
■ Port Jackson Sharks ($750): “Have a spine at the front of both dorsal
fins that can cause injury... is a difficult fish to acclimate and may not
eat.... Once eating well, it will eat virtually any crustacean or mollusk
in the aquarium and will also prey upon any sleeping fish small enough
for it to eat whole.”
■ Nurse sharks ($300): “Can reach a length of 4.3 m (14 ft) and a weight
of 330 lbs (150 kg).” Let the buyer beware.
In addition to outgrowing their confined quarters, all elasmobranchs
are carnivores, and most are predatory, which guarantees frustration if you
want to keep more than one fish in a tank. Any shark can inflict a painful,
damaging bite when handled.
Some saltwater rays are sold in the aquarium trade, but most grow too
large for a home hobbyist. We have seen electric torpedo rays (Torpedini-
dae) for sale for as little as $80, but we can’t imagine a more unsuitable
and dangerous aquarium species. Freshwater stingrays (Potamotrygonidae)
from the Amazon River basin are sold in pet stores and online. They have
an advantage over sharks because they are freshwater animals and gener-
ally easier to keep than saltwater fishes. Some are bred in captivity, which
is better than removing individuals from the wild. But they are expensive; a
typical 8-inch-diameter (20-cm) Motoro Stingray sells for $200 to $300 or
more (4-in stingrays may cost “only” $70)! And all but a couple of species
grow to over 3 feet across, which makes them unsuitable for most home
aquariums. Add to these problems the complication that it is illegal to sell
or own a freshwater stingray in many states. As you can discover by read-
ing posts on aquarium blogs, their care is complicated, their water quality
requirements are exacting, and they go from apparently healthy to dead in
a matter of hours (or shorter). And, oh yes, they do have that lethal barb,
which gets fouled up in any kind of net if you have to move one for any rea-
son, and then it can stab you as you try to untangle it.
Keeping freshwater fishes is relatively easy, but marine fishes—which
means 99% of elasmobranchs—are another matter altogether. Marine
fishes are more sensitive to water quality, temperature, food type, and dis-
ease than most freshwater fishes. Marine species are difficult to breed in
captivity and thus must be captured in the wild, often with methods that
destroy habitats and other animals. A responsible aquarist can avoid many
problems by purchasing fishes that are on the American Marinelife Dealers
Association’s Ecolist of species that are easily maintained (see http://www.amdareef
.com). Unfortunately, AMDA hasn’t posted new information on its website
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