| Rabbitfish |
any member of Family Siganidae, so named because of
their herbivorous feeding habits |
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| Radiole |
in certain polychaete annelids, a structure employed both for gas
exchange and in food capture, and that in aquarium species is often
strikingly colored |
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| Radula |
the rasplike feeding appendage of certian mollusks, the structure
of which is often used to distinguished among taxa |
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| Raptorial appendage |
any extension of the body employed primarily for prey capture, but
especially that of certain crustaceans |
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| Rasbora |
small, colorful cyprinide fish native to Asia, the most common of
which is the harlequin fish, R, heteromorpha |
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| Rasbora |
common name of the genus Rasbora, or its close relatives |
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| Recluzia |
an unusual marine snail that feeds on pelagic hydrozoans; sometimes
exhibited in specialized aquariums |
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| Redox |
potential the tendency for oxidation-reduction reactions to occur,
usually measured in millivolts; the higher the value, the more reactive
the solution |
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| Reefkeeping |
the hobby of maintaining coral reef organisms in aquariums |
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| Reflux |
to pass a liquid repeatedly over an absorptive or reactive medium
in order to alter the properties of the former |
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| Refugia |
areas deliberately provided in the design of an aquarium in which
certain species can seek shelter from potential predators in the same
tank |
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| Rehydrate |
to add water back to anything from which it has been removed |
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| Respiration |
the oxidative release of chemical energy from food molecules in
a living organism |
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| Reverse-flow filtration |
a arrangement that pumps water through the gravel covering the base
of the tank, thereby dislodging any solid waste material, and making
it available for collection by the power filter doing the pumping. |
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| Reverse osmosis |
(RO) unit a water purification device that forces feed water under
pressure through a semipermeable membrane, allowing only pure water
with reduced solute content to pass out as the product |
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| Rhinomuraena |
ribbon eels, Indo-Pacific fish once regularly imported for the aquarium,
but seldom successfully adapted to captive conditions |
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| Rhipocephalus |
a green seaweed with a calcified structure resembling a pinecone
emerging on a stick from a solid substrate |
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| Rhizome |
a rootstock, or food storage organ, formed from the root of a vascular
plant, usually creeping horizontally in the substrate, and giving
rise to new top growth along its length |
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| Rhodactis |
several species of Indo-Pacific disc anemones imported for minireef
aquariums, including a bright blue form from Tonga, bearing highly
branched tentacles on the oral disc |
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| Rhynchocinetes |
camel shrimp, or dancing shrimp, Indo-Pacific crustaceans having
a distinct hump in the carapace and found in groups often maintaining
contact and coordinated movement with each other |
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| Riccia |
crystalwort, a floating aquatic liverwort plant of wide distribution |
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| Ricordea |
a false coral genus once regularly collected in Florida and the
Caribbean but now largely protected by environmental regulation; it
can be propagated, although slowly |
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| Rivulus |
type genus of Family Rivulidae, from South America and CUba; one
species is known only from specimens in the aquarium trade |
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| Roe |
fish eggs |
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| Rostrum |
an extension of the canterior dorsal surface of the carapace of
some crustaceans, useful in identification |
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| Rotala |
flowering aquatic plants in the loosestrife family with upright
stems and opposite leaves, including both red and green species frequently
maintained in aquariums |
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| Rotifer |
any member of Phylum Rotifera, tiny microscopic animals of both
freshwater and marine habitats, improtant as a food source for many
aquatic organisms; at least one species, Brachionus plicatilus, is
employed extensively as a first food for larval marine fish |
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| RTN |
rapid tissue necrosis, a pathological condition of stony corals
caused by bacterial infection and susceptible to treatment with chloramphenicol |
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| Run |
in to operate a new aquarium without fish for a period of time to
permit the growth of desirable microorganisms and to assess equipment
performance |
