Moray Eels added to the
Gulf of Mexico tank
Tenn. (March 22, 1999) - They may look menacing - almost like
mythical sea monsters - but the Tennessee Aquarium's new additions
are more fascinating than frightening.
The two green moray eels, each about four-and-a-half feet
long, were added to the Gulf of Mexico tank in early March,
and they have been mesmerizing visitors ever since. Part of
the eels' allure seems to come from their fierce appearance
as well as their slow, serpentine way of swimming.
jaws and rows of sharp teeth leave no doubt that the moray eels
are efficient predators.
"Eels' mouths are hinged to move up and down, much like the
human mouth," said Thom Demas, volunteer dive coordinator. "However,
their mouths are also hinged in the center, below the nostrils.
This second hinge allows their mouths to open from side to side.
Green morays have very sharp teeth and each eel has an additional
row of teeth in the roof of its mouth. It may sound strange,
but the eels need these teeth to catch and eat their prey."
Moray eels also constantly open and close their mouths, displaying
those sharp teeth. This biting motion may appear to be an aggressive
behavior, but it is actually the way the eels breathe. Water
enters through the eels' mouths and is propelled over their
gills by the biting motion. The water is then expelled through
small holes, called spiracles, on each side of the eel's head.
Although the Aquarium's morays appear green, their skin is actually
dark blue in color. However, the eels are covered with a layer
of yellowish algae-containing slime that causes them to appear
green. These eels can also look brown, gray or gold, depending
on the type of algae living in this slime. Their long, lithe
bodies, dorsal fins and mouths full of needle-sharp teeth give
these nocturnal hunters their place at the top of the food chain.
In the wild, morays like to stay near home, hiding in the holes,
caves and ledges of reefs and rock formations. At night, the
eels become active, hunting for octopus, fish, crab and shrimp.
At the Aquarium, the eels enjoy a diet of squid and smelt, Demas
said. Eventually, herring will be added to their diet. Those
double-hinged jaws allow the morays to eat prey much larger
than one would expect, he added. Currently, the eels are being
fed three times each week. They are given about half a pound
of food at each feeding and a vitamin supplement to keep them
Although they have a reputation for aggression, moray eels should
be respected, not feared, Demas said. Eels are nearsighted and
rely heavily on their sense of smell to find food. For this
reason, divers at the aquarium don't feed these animals by hand.
Instead, three-foot tongs are used during feeding time.
"The eels wouldn't intend to bite divers, but because of poor
vision, they could misjudge and get a diver's finger or hand,"
Demas explained. "That is why we take the precautions that we
do. The tongs prevent this problem."
According to Demas, the maximum length for a green moray eel
is between seven to eight feet long. The Aquarium's eels currently
weigh in at 17 and 20 pounds. However, Demas said they will
probably continue to grow.
Demas added a fabricated rock to the Gulf of Mexico tank to
help the eels feel comfortable in their new environment. This
rock has several holes in it and provides a hiding place for
It is quite difficult to determine the gender of green moray
eels, so it is not known if the Aquarium's eels are male or
female. Regardless of their gender, it is highly unlikely that
the eels will reproduce. Green morays have not successfully
reproduced in captivity. In the wild, moray eels produce leaf-like
larvae, which floats on the top of the water until they are
ready to metamorphose. Once metamorphosed, juvenile green morays
then swim to the bottom of the ocean.
Tennessee Aquarium in Chattanooga is the largest freshwater
aquarium in the world. Built with private contributions, this
non-profit educational organization is dedicated to the understanding,
conservation and enjoyment of the Tennessee River and related
ecosystems. Admission is $10.95 per adult and $5.95 per child,
ages 3-12. The Aquarium is open every day except Thanksgiving
and Christmas and is accessible to people with disabilities.
The Aquariums TDD number is (423) 265-4498, and FM assistive
listening devices are available on site. For more information,