| Echinaster |
a common sea star of the tropical Atlantic and West
Indies often imported for the marine aquarium; predatory on bivalve
mollusks and other sessile invertebrates |
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| Echinoderm |
literally "spiny skin," any member of Phylum Echinodermata,
exclusively marine invertebrates with radially symmetrical bodies
and a water vascular system found in no other animal group |
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| Echinodorus |
Amazon sword plants, popular freshwater aquarium plants from North,
Central, and South America producting a rosette of leaves and bearing
flowers on a stalk extending above the water surface; under aquarium
conditions, some regularly produce runners bearing plantlets |
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| Echinometra |
rock-dwelling sea urchins sometimes imported for algae control in
the aquarium |
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| Echiurid |
any of the wormlike marine inverterbrates in the Phylum Echiurida,
characterized by an eversible, flattened appendage used for capturing
particulate food and commonly introduced into the marine aquarium
with live rock |
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| Ecolabeling |
a proposed system for categorization of species according to their
relative adaptability to captive husbandry, designed with the goal
of reducing the number of nonadaptable species collected for the aquarium
trade |
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| Ecosystem |
all of the physical and biological components of a specific geographic
area and the interactions among them, usually defined by a dominant
feature, such as a coral reef or lake |
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| Ecotype |
a variety of a species that is characteristic of a particular ecosystem
or habitat |
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| Ectoderm |
the outer layer of embryonic tissue, giving rise to such structures
as the skin and nervous system |
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| Ectoparasite |
one attached to the outer body surface of the host organism |
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| Eelgrass |
common name for the freshwater plants in the genus Vallisneria,
and for the marine flowering plant Zostera marinae; either may be
kept in an appropriate aquarium |
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| Eichhornia |
water hyacinths; freshwater neotropical plants with long, pendant
root systems and floation structures at the bases of the leaves; a
pest plant in some tropical habitats, though often grwon in aquariums
and especially in garden ponds for their attractive flower spikes |
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| Eigenmannia |
glass knifefish, particularly E. virescens found in freshwater floodplains
of tropical South America and sometimes imported for aquariums |
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| Elasmobranch |
any of the cartilaginous fish, including sharks, skates, and rays
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| Electric shock organ |
specialized structures possessed by some fish that permit them to
generate a charge that ranges, depending upon the species, from millivolts
to several hundred volts; such discharges are utilized for a variety
of purposed from mate recognition to food capture to defense |
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| Electrolytes |
solutions that conduct electricity |
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| Electrophorus |
the electric eel, E. electricus |
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| Element |
a chemical substance composed of only one type of atom and thus
irreducible to components by ordinary chemical means |
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| Eleocharis |
spikerushes, sedge plants of wide distribution with extremely narrow,
elongated leaves, often used for decorative effect in planted aquariums |
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| Eleotris |
sleeper gobies, Family Gobiidae, found in brackish water habitats |
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| Ellisella |
marine gorgonian corals often with attractive coloration and frequently
imported for the aquarium |
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| Elodea |
E. densa, often incorrectly called "Anacharis" in pet
shops; this vining, dark green, bushy plant, usually sold in bunches,
does best in cool, rather than tropical, aquariums or in a garden
pond |
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| Emergent |
said of leaves or flowers that are borne above the water surface
by an otherwise aquatic plant |
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| Encrusting |
forming a thin, usually hard layer on a solid substrate |
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| Endangered species |
one recognized under law as so imperiled that a single event could
render it extinct in the wild; also applied by ecologists to any species
considered i peril of extinction, regardless of its legal status |
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| Endoderm |
the inner embryonic tissue layer giving rise to such structures
as the digestive and respiratory systems |
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| Endodermal |
of or having to do with the endoderm |
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| Endoecism |
a symbiotic relationship between two species in which one lives
within the body of the other but does no harm to it |
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| Endoparasite |
one that lives inside the body of the host organism |
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| Entacmaea |
bubble-tipped anemone, a host for many species of clownfish and
the one most readily maintained under aquarium conditions |
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| Entoproct |
any member of Phylum Entoprocta, small, colonial marine Invertebrates
that encrust solid substrates and feed by means of a specialized organ,
the lophophore |
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| Enzymes |
protines that catalize chemical reactions in living cells |
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| Epalzeorhynchos |
the red-tailed and red-finned "sharks" of Southeast Asia,
actually cyprinids: often included in freshwater community aquariums |
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| Epidermal |
having to do with the epidermis, or outer layer of skin |
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| Epiplatys |
egg-laying toothed carps of tropical Africa, with several strikingly
colored species kept by killifish enthusiasts |
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| Epithelium |
a layer of tissue exposed to the environment, including the epidermis,
but also including the linings of the alimentary tract and other internal
surfaces; the latter often bears cilia and secretes mucus |
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| Epizoic |
living upon the outer body surface of an aminal, but doing no harm
to it |
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| Epsom salt |
magnesium sulfate, often combined with sodium chloride to produce
a rudimentary form of synthetic seawater |
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| Equetus |
reef drums, usually black-and-white-striped marine fish rehularly
imported from Florida and the West Indies |
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| Erythromycin |
an antibiotic sometimes added to the marine aquarium for control
of blue-green algae: it is extremely toxic to nitrifying bacteria
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| Erythropodium |
a soft coral with large, flowing polyps and a reddish colored, rubbery
skeleton that grows over solid surfaces |
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| Escenius |
Indo-Pacific blennies, the most commonly imported species of which
is E. bicolor, the orange and black bicolor blenny |
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| Esophagus |
the tube leading from the mouth to the stomach |
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| Esox |
pikes, predatory fish of North American waters that hide among vegetation
and ambush prey; often exhibited in large aquariums |
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| Esterifled |
having formed an ester, or chemical bond of the general form |
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| Estuary |
an ecosystem formed where a river meets the ocean, and characterized
by fluctuations in salinity due to tidal movements |
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| Etroplus |
the onlsy genus of cichlids found on the Indian subcontinent; popular
with brackish-water aquarium enthusiasts |
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| Eucarids |
true shrimps, decapod crustaceans in several families, including
numerous species regularly exhibited in marine aquariums |
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| Eukaryote |
a living organism comprised of cells having a distinct membrane-bound
nucleus and other subcellular structures enclosed in membranes |
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| Eunicea |
photosynthetic gorgonian soft corals desctipively named "knobby
candelabra" |
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| Euphausid |
krill, shrimplike marine crustaceans often sold in freeze-dried
or frozen form as aquarium food |
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| Euphyllia |
stony corals, four species of which are popular with minireef enthusiasts
because of their unusual tentacle shapes and ease of care |
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| Euthanasia |
mercy killing, or the deliberate killing of and organism to spare
it from pain or suffering |
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| Evolution |
biological change resulting in the development of new species from
ancestral species due to natural selection acting upon genetic variability
in the latter |
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| Excreta |
solid wastes produced by an animal; feces |
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| Excretion |
the physiological process of waste elimination in cells or organisms |
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| Excurrent opening |
one, as in mollusks, from which water flows out toward the environment
|
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| Exopthalmus |
a disorder of both marine and freshwater fish in which the eyeball
protudes noticeably from the eyesocket, symptomatic of a varitey of
pathological conditions |
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| External filter |
any aquarium filter not located within the tank itself |
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| Extinction |
the loss of a species from its ecosystem |
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| Extratentacular |
literally, "outside the tentacles," referring to the process
of daughter colony formation by certain species of stony corals, in
which an offspring buds from the outer surface of the parent colony |
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| Eye |
a nulticellular organ sensitive to light |
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| Eye Stalk |
the short appendage supporting the visual organs of many mullosks
and crustaceans |
