EELS! EELS! EELS! EELS!
By Jim Wolf MS. Marine Biology
ODYSSEA ( MASLA ) Volume 5, Issue 1
Eels hold a very distinct position in the fish world. There are many
families of eel like fishes, however true eels have a few unique features.
As juvenile fish most are clear as glass and float upon the open ocean
and are called Elvers. They then settle out and take up a adult life style.
Eels are all predators that enjoy whole shrimp, clams, or fish about
twice a week. Most eels are very communal, only bothering things
they perceive as being food. A well sealed aquarium lid is a must, because
these animals are very good at escaping.
Their sense of vision is poorly developed in these animals, but they
have excellent sense of smell. A spacious aquarium is compassionate, but
they can be confined to very small aquariums with little ill effects. A
small cave made of rocks,a low light environment, strong mechanical filtration
and no aggresive tankmates make for happy eels.
Despite the huge numbers of eel species there are only two families
of eels seen in the hobby.
Conger eels of the family Anguillidae are true eels, and are
extremely hardy. The dominant Eel family is Muraenidae, which
includes the familiar Moray Eels. There are about 100 species, and 6 genera
make their way into the hobby.
Gymnothorax - This along with the genera Muraena and Echidna
make up the fish recognized as the Moray Eels. There are about 50 plus
species in this group, and some can attain a length of up to 10 feet in
the wild. In captivity they usually do not exceed three feet. These animals
are very tolerant of a wide range of water conditions, and violate the
classic 1" of fish for every 2 gallons of water rule. The number of fish
that you can successfully put into a salt water aquarium is generally placed
at 1 " of fish for every two gallons of water. Well.....eels do not apply,
since even at foot long eels would then require a 24 gallon tank. So one
foot eel equals roughly 3 inches of fish, since most of the eel is "all
The moray eel that does fit the rule is the Zebra Banded Moray (Gymnomuraena
zebra) in that it does not actively eat fishes. This common species
eats almost exclusively crustaceans, since it possess small dull teeth
that are only occasionally used to eat fish.
Rhinomuraena - These are the colorful ribbon eels. The blue specimens
are actually juveniles of the adult black form. Ribbon eels have very enlarged
nasal nares (AKA nostrils) They are defenseless, fragile and do well only
if placed into well established aquarium and their food needs are attended
to. They feed at dusk, so subdue the lighting and tempt them with live
glass shrimp. Over time they will accept frozen fish, squid, and clams,
but remember to feed them at dusk and insure that they get some food.
Myrichthys - This is the rare Golden Spot Eels. They bury themselves
in the sand and are quite hardy albeit defenseless. They can be identified
by their barrel shaped nostrils and large gold spot. They eat similar food
as other Moray eels.