| Habitat |
the geographic locaity, together with its biological
components, in which a species is typically found |
| |
|
| Halichoeres |
marine wrasses, Family Labridae, many species of which are adaptable
to aquarium care |
| |
|
| Halimeda |
a mactrophytic green marine alga with a calcified skeleton consisting
of flattened plates or disks attached to each other at the edges |
| |
|
| Haplochalaena |
the blue-ringed octopus, a species sometimes imported, but that
should be avoided by aquarists because of the toxic venom delivered
by its deadly bite |
| |
|
| Haplochromis |
one of many genera of chiclids found in the rift lakes of eastern
Africa |
| |
|
| Hard water |
water that contains dissolved salts of calcium and magnesium in
a concentration greater than 200 parts per million |
| |
|
| Hatchling |
any organism that has recently emerged from the egg |
| |
|
| Hawkfish |
marine fish, Family Cirrhitidae, that characteristically perch atop
a coral head or other prominence to watch for prey; many are popular
aquarium fish |
|
|
| Head |
the anterior portion of bilaterally symmetrical animal, bearing
sence organs such as eyes or antennea, and enclosing the brain |
| |
|
| Head-and-lateral-line erosion |
(HLLE) a condition observed in some marine and freshwater fish,
notably those in Families Acanthuridae, Pomacanthidae, Pomacentridae,
and Chiclidae, but not restricted to these, in which the scales and
epidermis of the face and along the lateral line erode away, leaving
depigmented areas that may become infected; while the exact cause
is unknown, studies suggest that the condition is associated with
deficiences of vitamins C or A or both |
| |
|
| Heliofungia |
plate coral, a stony coral with a rounded, biscuit-shaped skeleton
and long tentacles often tipped in pink; it is a bottom-dwelling species
capable of slow movement across the substrate and sometimes confused
with a sea anemone; difficult to maintain unless provided with bright
illumination and appropriate water conditions |
| |
|
| Heliopora |
blue coral, the monospecific genus of the anthozoan Order Coenothecalia,
usually displayed in the aquairum as a dead skeleton, which is light
blue in color |
| |
|
| Hemiancisturs |
South American suckermouth catfish useful for algae control in the
aquarium |
| |
|
| Hemichromis |
jewl cichlids, colorful West African species that are highly territorial
and aggressive, but often maintained in aquariums |
| |
|
| Hemigrammus |
South American characins of which numerous species are good community
aquarium fish |
| |
|
| Heniochus |
pennant butterflyfish, found in the Indo-Pacific and unlike other
members of their family, living in schools and feeding upon planktonic
organisms in midwater |
| |
|
| Hepatus |
box crabs with a pale-colored carapace bearing bright maroon blotches;
they have chelae adapted for feeding on snails and are often exhibited |
|
|
| Herbivore |
any organism that has living plant matter as its primary diet |
| |
|
| Hermaphroditism |
a condition in which a single individual possesses both male and
female reproductive organs, either simultaneously or at different
stages in its life cycle |
| |
|
| Hermatypic |
corals that contain symbiotic dinoflagellates known as "zooxanthellae" |
| |
|
| Heros |
South American cichlids, especially the severum, H. Severum |
| |
|
| Herpolitha |
slipper coral, a bottom-dwelling, mobile stony coral with an elongated
skeleton rounded on either end |
| |
|
| Heteractis |
tropical anemones of the Indo-Pacific, at least three of which are
host to anemonefish; they are often kept in aquariums although they
are difficult to maintain successfully |
| |
|
| Heterandria |
small, live bearing fish from the costal southeastern United States,
including the least killifish, H. formosa, the smallest North American
vertebrate |
| |
|
| Heteranthera |
a pondweed of trompcal and subtropical America, cultivated for its
kidney-shaped floating leaves |
| |
|
| Heterocercal |
a type of caudal fin found in primitave fish, including gars, sturgeons,
sharks, paddlefish. and bowfins, in which the upper lobe arises from
the upturned terminal vertebrae, and the lower lobe from the ventral
portions of the same bones |
| |
|
| Heterotroph |
any organism that obtains energy by consuming preformed food molecules |
| |
|
| Heterotrophic |
of or having to do with heteroph or its mode of nutrition |
| |
|
| Hexacoral |
a colonial anthozoan with tentacles in multiples of six |
|
|
| Hinge ligament |
the tough, flexible tissue that secures the two shells of a bivalve
mollusk at the area where they rotate against each other |
| |
|
| Hippocampus |
seahorses, comprised of some 30 species distributed worldwide inshallow
seas |
| |
|
| Hippopus |
a monospecific genus of giant clams, regularly produced by aquaculture
and maintained in minireef aquariums |
| |
|
| Holdfast |
any structure produced by a sessile organism for the purpose of
anchoring it to a solid substrate |
| |
|
| Holochathus |
large marine angelfish of the tropical Atlantic and Caribbean |
| |
|
| Holothurid |
a sea cucumber, Phylum Echinodermata, Class Holothuroidea |
| |
|
| Homeothermic |
referring to an organism with the ability to maintain a constant
internal body temperature; warm-blooded |
| |
|
| Homocercal |
the type ofcaudal fin found in most bony fishes, in which the vertebral
column terminates at the fin base |
| |
|
| Homogeneity |
uniformity; in biology, usually referring to a lack of variation
among the individuals comprising a population |
| |
|
| Hood |
an enclosure housing light fixtures for aquarium illumination, usually
incorporating a cover for the entire tank |
| |
|
| Hoplolatilus |
sand tilefish, Family Malacanthidae, some species of which are small
enough to be accommodated in a suitable aquaeium |
| |
|
| Hoplosternum |
South American armored catfish often confused with Corydoras, which
they closely resemble |
|
|
| Hybrid |
the offspring resulting from crossbreeding between two different
species |
| |
|
| Hybridization |
the process of hybrid formation, either in nature or the deliberate
crossing by human intervention of two species in an effort to produce
offspring with combination of parental traits |
| |
|
| Hydnophora |
horn coral, a stony coral, usually bright green, popular with reef
aquariusts because of the ease of propagation |
| |
|
| Hydra |
a freshwater hydrozoan resembling a tiny sea anemone that is sometimes
a problem i breeding aquariums because of its ability to catch and
eat fish fry |
| |
|
| Hydrocotyle |
water pennywort, a low, creeping aquatic or bog plant bearing rounded
leaves with scalloped edges |
| |
|
| Hydrogen ion |
a hydrogen atom that has lost its electron, the concentration of
which determines the pH of a solution |
| |
|
| Hydrogen peroxide |
(H2O2) a compound sometimes added to aquarium water to increase
the oxygen content as it dissociates rapidly into water and free oxygen;
also used as a disinfectant for treating wounds in fish |
| |
|
| Hydroid |
any member of the cnidarian Class Hydrozoa, but most oten applied
of the flowerlike polyp form of these organisms |
| |
|
| Hydromedusa |
the free-swimming stage in the life cycle of a hydrozoan, shaped
like a bell or umbrella and superficially resembling a sea jelly |
| |
|
| Hydrometer |
a device for measuring specific gravity |
| |
|
| Hydrophilic |
literally "water loving," said of substances, such as
oils, that do not readily dissolve in or mix with water |
| |
|
| Hydroxyl |
a hydroxide ion, OH+, formed when a water molecule dissociates |
| |
|
| Hydrozoan |
any member of the cnidarian Class Hydrozoa, characterized by a life
cycle exhibiting alternation between a polyp stage and a medusa stage |
| |
|
| Hygrophila |
fresh water flowering plants of the Acanthus family sold as bunches
of rooted cuttings, of rapid growth under aquarium conditions |
|
|
| Hyphessobrycon |
a large genus of small South American characins including some of
the most popular species for freshwater community aquariums, such
as the bleeding heart tetra |
| |
|
| Hypochlorite |
an ion formed from chlorine and oxygen that is a strong oxidizer;
household bleach, sokium hypochlorite, is used as a sterilizing agent
in various aquarium-related applications |
| |
|
| Hypostomus |
suckermouth catfish from South America, often maintained in freshwater
aquariums for control of algae growth |
| |
|
| Hypseleotris |
gudgeons, Family Gobiidae, from Australia and New Zealand |
| |
|
| Hypsypops |
the Garibaldi damselfish, H. rubicunda, still sometimes seen in
aquarium shops, despite its legal status as a protected species and
requirement for cool water; it is found off the California coast and
lives in kelp forests |
