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“Out of sight is out of mind”, reminiscent of Philip Slater’s
“Pursuit of Loneliness” work on societies… And prompting of the real eel
situation on Hawai’i’s shallow reefs; many, MANY anguilliform fishes to
be found t/here. In assays with poisons like Rotenone years back, and
economic true anesthetics in more recent, it’s found that more than half
the biomass of these areas occurs as various eel species. And holy moly
(!); a BUNCH of species as well; some forty two Morays alone can be
found in the 50th US State’s waters, along with sixteen Snake
and Worm Eels, and four more shallow species of Conger Eels. This is
their story of related natural history and aquarium use.
“I’m in the Mood for A Moray”….
Moray species are only second (behind Wrasses) in being numerous here;
and though mostly unseen, hidden in rock by and large by daylight, their
presence in the way of predatory pressure is strongly felt here. Most
species are strongly piscivorous (fish eating), with the two most
popular “captive use” species being more crustacean consumers. Let’s
list them in order of aquarium desirability and use: The first two are
unsurprisingly the non-fish eaters alluded to above; with molariform
rather than sharp spikey teeth, they use for mainly capturing and
crushing crabs and other crustaceans. These two, the Snowflake and Zebra
used to make up more than 90% of Eels shipped out of Hawaii for the
trade.
Other Morays Collected:
In dribs and drabs a few other species have been captured for ornament;
in traps, by hook and line, and netted by daring scuba divers by night.
Again, these were only ever moved in one at a time quantities; and
though being better for the trade from Hawaii, are collected no more.
Other Morays Not Collected:
Conger Eels and Garden Eels,
Family Congridae:
Conger eels are kept by regional public aquariums, but are rare as
chicken teeth in the ornamental trade. This is a shame as some do stay
small enough (less than two feet) and are beautiful and comical in their
behavior and appearance. There are some thirteen species of Hawaiian
Congrids described, though there may well be a few other deep water
species yet to be discovered. There are some adventurous/daring
LFS that do sell Garden Eels, and again public displays, but I’ve yet to
see any Hawaiian Garden Eels offered to hobbyists.
Snake Eels and Worm Eels, Family Ophichthidae:
Like Congrids, these fishes are confined to the realm of huge,
specialized public aquaria; needing very deep sand beds to burrow in;
and even then is rarely seen on exhibit. There are sixteen species
recorded from here if you don’t count the six not found in the Johnston
Atoll, but not northward. Other Anguilliform Species
Found in Hawaii:
Of the fifteen families that make up the Order of true eels
(Anguilliformes), there are two more with representatives in the 50th
State; the Spaghetti Eels (Moringuidae) and False Morays (Chlopsidae).
These fishes are never found in the trade, being very reclusive and
unattractive; I’ve mentioned them here simply for the sake of
completeness.
Compatibility:
Other than the two-three molar-toothed non-fish eating species (the
Snowflake, Many-Barred and Zebra Morays), none of the “aquarium-eels”
from Hawaii are to be trusted with stocking alongside other fishes. In
fact, all can consume unattached invertebrates, and everything is in
danger of being bumped and knocked about when they go on their nightly
forays. To put this more bluntly and in a positive statement; they are
best kept in a species/specimen only setting for their display alone.
To repeat; yes; there are other Eel species from here and elsewhere that
aquarists take calculated risks with. Eventually, unless the eel is
small, tankmates large enough, smart enough and fast enough; there are
losses.
Selection:
Picking out a healthy eel is an easy, straight-forward procedure; as
they’re generally good shippers; and amazingly adept at recovering from
physical traumas. Look for “bad spots” on the body; reddening of sores,
fin origins and especially damage around the mouth. Do ask that the
prospective purchase be fed in front of you; and if it is feeding, it is
very likely good to go. Systems: Escape Artists ala
Houdini:
Large, well-filtered, covered and with solid décor sums up what it takes
to keep a puhi. Foods/Feeding: NOT By Hand:
Yes; they can and do bite… and there is growing evidence that venom may
be involved in at least some species, but the physical damage alone,
complicated with bacteria associated with their mouth should keep your
hands out of their system. Use a feeding stick or such for offering food
items; and long handled tools for doing maintenance in their system.
Beware of limited and too Thiaminase-prompting food items. Feeding only
shrimp, silversides, fillets (vs. whole small fish)… leads ultimately to
nutritional deficiency syndromes. Best to secure “mixed seafood” frozen
in serve-able portions (often sold for humans; to make seafood stews),
to defrost and feed a piece at a time.
Eels are subject to goiters more so than most fish groups; the easiest
way to avoid them is regularly dosing with “coral” iodide-ate; at stated
dosage every water change. About Eel Conservation:
A cogent argument can be made for preserving eel diversity and
abundance; such speciation and numbers provide predator-prey pressure,
keeping eel-food fishes, cephalopods and crustaceans “fit” after all.
And some valid position can be advanced for not collecting them for the
trade, leaving local fishers and their natural predators to “thin the
herd”; humans avoiding larger specimens for righteous fear of ciguatera
poisoning.
Are there too many eels? When western folks became established in
Hawaii in the early nineteenth century, they produced recordings of
impressions of fish and octopus stocks there that state there were these
other animals in abundance….
Cloze:
Hawaii IS the land of the Puhi! But unfortunately NOT for the aquarium
hobby; as NONE of the eels found there are on the “white list” for
collection (Walsh 2013). Be that as it may, none of those used for
hobbyist aquariums are endemic either; and can be purchased from other
geographies. At least you now are aware of just how many species of
eels/puhi are to be found in Hawaiian waters, and can look forward to
going there, visiting them first hand.
Bibliography/Further Reading:
Fenner, Robert. 2000. The Zebra Moray Eel, Gymnomuraena
zebra. FAMA 7/00.
Gonzalez, Deane. 1976. Puhi. The Marine Aquarist (mag.), V. 7 (7).
Randall, John E. 1996. Shore Fishes of Hawaii. Natural World
Press, OR. 216 pp. Walsh, William J. 2013.
Background Paper on West Hawaii Aquarium White List
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