By Bob Goemans
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The 'LIVING' Marine Aquarium Manual

Basic and Advanced Husbandry for the 'Modern' Marine Aquarium

by Bob Goemans


Actinic Bulbs: Produce light at the blue end of the visible light spectrum. Used in aquariums contasining photosynthetic invertebrates.

Activated Carbon: A filter medium used in both internal and external filters to remove toxic substances.

Active transport: Movement of materials through the cell membrane against a diffusion gradient.

Adenosine triphosphate (ATP): A chemical compound found in all cells derived from sources loosely termed as nutrients or energy. Of particular importance to enable energy expending uses by cells for motion, viability, and reproduction.

Adsorption: The ability to attract and concentrate upon surfaces of molecules (gases, liquids, and dissolved solids).

Aerobic: That, which requires oxygen to survive. Nitrifying bacteria is considered aerobic, since they require oxygen to live and grow.

Airstone: A device usually connected to an air pump and which diffuses oxygen into water, helping also to create water movement.

Algaecide: A chemical algae killer.

Alkalinity: The capacity of water to neutralize a strong acid. Basically the amount of carbonates CO3 and bicarbonates HCO3- found in water.

American Marinelife Dealers Association (AMAD): A non-profit organization founded in1995 by John Tullock. Its sole purpose is to help dealers involved with the retailing of saltwater fish. The intent of the AMAD is to maintain standards of practice within the industry by helping dealers become responsible through awareness and responsible ethics.

Ammonia (NH3): A chemical compound that is the primary nitrogen-containing end product of protein metabolism and the breakdown of living or formerly living matter.

Amphipod: Small crustaceans belonging to the Order Amphipoda, including the genus Grammarus. Typically introduced into aquariums via live rock, they can be used as aquarium fish food.

Anaerobic: Able to survive without oxygen. Anaerobic bacteria, some of which consume nitrates, live in oxygen-poor environments, such as in the lower areas of deep sandbeds or deep within that of live rock.

Anecdotal: Evidence or information based upon individual examples or informal case reports not from scientific or controlled studies.

Anion: A negatively charged ion.

Anoxic: Areas that have an oxygen level between 0.5 - 2.0 ppm.

Anthelminthic: Drug use in the control of platyhelminthes, a phylum of organisms that include flatworms, flukes and tapeworms. Medications such as formalin and organophosphates are good examples.

Aragonite: A naturally occurring porous mineral high in calcium carbonate that tends to dissolve slowly at a pH slightly below 8.2.

Artemia: A small organism used as live food, e.g., brineshrimp.

Assimilation: The manufacture of reserve food or protoplasm, involving anabolism or constructive metabolism.

Assimilatory denitrification: The act of using nitrate to build other nitrogen compounds for metabolic use, e.g. ammonium.

Autecology: The ecology of an individual organism or species.

Autotrophic: Refers to living organisms that are capable of producing their own energy sources. Autotrophs typically consume one thing unlike heterotrophs, which are capable of using many food sources.

Balance: The result of steady-state equilibria.

Benthic: An organism living near or on the bottom substrate.

Berlin System: A natural filtration method relying of copious amounts of live rock, strong water circulation, excellent lighting, and usually Kalkwasser for control of alkalinity parameters.

Bicarbonate ion (HCO3-): The main buffer in water under a pH of 9. In cases where the pH is over 9, carbonate becomes predominant. Produced by the dissolution of carbon dioxide in water.

Bilateral: Involving or occurring on two sides, such as the eyes or pectoral fins of a fish, for example.

Biochemical Oxygen Demand (BcOD): A measure of the amount of oxygen removed from aquatic environments by aerobic micro-organisms for their metabolic requirements.

Biodegradable: Capable of being decomposed by biological activity.

Biofilm: A thin layer of microscopic organisms growing on a wet or submerged surface.

Biogenetic law: The statement that the development of the individual repeats the development of the race.

Biogenic: Production of living organisms by living organisms.

Biogeochemical: The combination of biological representatives and geological conditions that result in the essential chemical activities.

Biogeochemistry: The transformation and movement of chemical materials to and from the bodies of living organisms throughout the aquarium.

Biological Filtration: The use of bacteria to change toxic compounds into safer compounds.

Biology: The science of life.

Biomass: The total mass of organic material of a species per unit of area or volume. The term is used to express population density.

Biome: A major biotic community characterized by a predominant life form.

Biosphere: The living Earth. The parts of air, land and water that contain and support living organisms.

Biota: The combined flora and fauna of a region.

Biotic potential: An expression of the rate of reproduction of an organism.

Bioturbation: Disturbing and altering of a surface or substrate by physical activity of organisms such as worms digging tunnels.

Botany: The science of plant life.

Brackish: Water that is slightly less salty than normal seawater.

Buffer: A substance, which alters or adjusts pH; that which maintains a constant pH.

Calcareous: Composed of or containing calcium carbonate or calcium in its structure.

Calcium (Ca++): One of the major cations in water and a principal hardness component and essential to life.

Calcium Carbonate (CaCO3): Non water-soluble salt existing in two crystalline forms - trigonal calcite and orthorhombic aragonite.

Calcium Hardness (KH): A fraction of the alkalinity that is in stoichiometric equivalence with divalent cations. 1 KH = 17.8 ppm of alkalinity measured as calcium carbonate.

Carbohydrate: A sugar or a condensation product of sugars.

Carbonic Acid: A weak, unstable acid (H2CO3) formed when carbon dioxide combines with water.

Carbon Dioxide (CO2): A product of carbon oxidation in aerobic metabolism and combustion. Dissolves in water to form carbonic acid and bicarbonate ion.

Carbonate ion (CO3): An anion that will accept a proton (H+) to become HCO3-.

Carnivore: A flesh eating animal.

Cation: A positively charged, usually metallic ion. Exceptions are the hydrogen ion (H+) and the ammonium ion (NH). 4+

Caudal: Referring to the tail.

Caudal Peduncle: Narrow, bony portion of the body of a fish located just before the caudal fin.

Cell: The fundamental single unit of structure and function in organisms.

cf: an abbreviation of the Latin word "conferre" meaning to compare, when used in the name of a species suggests the name is tentative, and is being used to compare it to an already known correctly described species.

Channeling: The formation of areas of increased flow due to obstructions elsewhere.

Chelated: Refers to a condition whereby a chemical, typically a heavy metal, is bound for stability by chelating compounds, such as EDTA. Chelated coppers are more stable in solution, but since the chelation renders it less toxic, must be dosed at higher concentrations to be effective.

Chemical Equilibrium: The state of dynamic balance between two or more competing chemical reactions.

Chemosynthetic/Chemosynthesis: Synthesis in which the energy for the synthesis is derived from a chemical reaction. Involved in photosynthesis.

Chloramine: A compound of chlorine and ammonia that makes the chlorine more stable in supply pipes so as to disinfect the supply of drinking/tap water.

Chlorophyll: The pigment of green plants essential in utilizing light for photosynthesis.

Cilia: Hair-like processes that is often used for food collection or locomotion.

Citric acid cycle: The cycle of chemical reactions in aerobic respiration by which the carbons of the acetyl group are oxidized to carbon dioxide; also called Krebs cycle.

Classification: The grouping of organisms on the basis of fundamental similarity.

Colony: A group of organisms of the same species living together.

Copepods: Very small crustaceans belonging to the large Class Copepoda. Some are main food sources (primary producers), and are planktonic, while others are ectoparasites of fish, causing disease.

C:N: A ratio between carbon and nitrogen. In aquatic sediments it's often measured near 7:1

Cycle: A complete course of actions or a series of events which occurs repeatedly in the same progression, e.g., energy cycle.

Deleterious: Harmful, dangerous or otherwise unfavorable. Overdosing with copper, for example, is deleterious to many fish.

Denatured: Lacking natural qualities or characteristics. Sometimes caused by degradation.

Destructive denitrification: See dissimilatory denitrification.

Differentiation: The process by which different types of cells, tissues, or organs are derived from a common pattern.

Diffusion: The movement of a fluid down a gradient from an area of higher concentration to an area of lower concentration.

Digestion: Preparation of food for absorption and assimilation, by hydrolysis.

Dinoflagellate: Algal protozoans, which are typically characterized by having two flagella and a cellulose covering.

Dinospore: A stage in the life cycle of certain protozoans, such as in the case of Amyloodinium. During the dinospore stage of Amyloodinium, newly hatched parasites (daughter cells) are released into the water to find a new host.

Dissimilatory denitrification: The action of the nitrate molecule being broken into combinations of its parts, i.e., nitrogen and oxygen.

Dormant: Not growing or functioning; not active. A dormant, encysted parasite may be considered to be in a resting or inactive state.

Dorsal: Upper surface or back of an animal.

DNA: Deoxyribonucleic acid - carrier of genetic information.

Dylox: A trade name for an organophosphate, used in the treatment of certain metazoan parasites, such as trematodes.

Ecology: The scientific study of the interrelationships of plants, animals, and the environment. In recent years the word has sometimes been misused as a synonym for environment. The principles of ecology are useful in many aspects of the related fields of conservation, wildlife management, forestry, agriculture, and pollution control. The word ecology, from the Greek word OIKOS, ("house," and logos, "study of") which is generally believed to have been coined by Ernst Haeckel who used and defined it in 1869. The historical roots of ecology lie not only in natural history, but in physiology, oceanography, and evolution as well. It has occasionally been called scientific natural history.

Ecosystem: A biotic community and its abiotic environment; considered as a unit.

Ectoparasite: An external parasite – one that lives on the outside of the body.

Elasmobranch: Refers to a group of fish possessing plate-like gills, such as sharks and rays.

Electromagnetic Field (EMF): Electrons in motion create a magnetic force or field.

Energy cycling: The elements used to produce organic compounds are required in a variety of forms by both plants and animals. Photosynthesis is the ultimate source of biological energy through the utilization of solar energy. Eventual breakdown of the organic compounds results in the cyclic return of nutrients to the environment for repeated use. This cyclic use and return of nutrients is considered an ecosystem characteristic.

Energy flow: Transfer of energy from sunlight to producers and through the levels of consumers.

Enzymatic: Coming from or being produced by enzymes.

Enzyme: A catalyst characteristic of living organisms.

Emaciated: Having a starved appearance.

Endemic: Restricted to and found naturally at a single location.

Enzyme: A catalyst characteristic of living organisms. An enzyme is a substance, which causes biochemical reactions to occur.

Epithelium: A cellular structure, which forms the outer layer (skin) of teleost fish, for example.

Equilibrated: To cause or effect equilibrium.

Equilibria: The degree to which a chemical reaction proceeds to form useful product(s) and the time required to complete the conversion(s) - two important aspects of modern chemistry. This chemical kinetics is the study of factors important to the speed at which a reaction forms product molecules. The final distribution of products and unconsumed reactants is often predetermined by the nature of the process and is representative of the chemical equilibrium or balance that is achieved.

Equilibrium: A state of balance between interacting or opposing forces of energy.

Equistatis: From the words equi and statis or equal and one. State of balance from equilibrium among opposing forces, sometimes in a chaotic environment.

Erythematic: Referring to a condition, which is evident by a redness of the skin, possibly caused by a bacterial infection.

Eutrophication: The process by which a body or volume of water becomes rich in nutrients, often exhibiting low oxygen or an increased oxygen demand on any oxygen present.

Euthanized: To put to sleep, or otherwise relieve suffering or the spread of disease by killing an animal painlessly to relieve suffering.

Evolution: The process by which all living things have developed from primitive organisms through changes occurring over billions of years, a progression that includes the most advanced animals and plants. Exactly how evolution occurs is still a matter of debate, but that it occurs is a scientific fact. Biologists agree that all living things arose through a long history of changes shaped by physical and chemical processes that are still taking place. It is plausible that all organisms can be traced back to the origin of life from inanimate matter.

Exophthalmia: Popeye. A condition or symptom, which is evident by the distention of the eye of fish, typically a result of a build-up of fluid or gas from an internal bacterial infection. Can either be unilateral (on one side) or bilateral (on both sides).

Factors of the environment: The media in which organisms live (including specific nutrients); the substrata on which they live; the climate in all its aspects; and, the presence of other organisms of the same and different species are all factors of the environment. We describe the media in terms of more or less stable physical and chemical properties and climate in terms of such changeable attributes as temperature and moisture.

Facultative: Ability to live under varying conditions, e.g., pH and oxygen.

Fat: A glyceryl ester of fatty acids - compound of glycerol and three fatty acid molecules.

Filtration: The removal or reduction of unwanted organic and inorganic matter from water.

Finite: To have discriminate or measurable limits.

Fixation: Converting elements and molecules from a gaseous to a usable solid form, e.g., nitrogen fixation.

Flagella: Whip-like extensions of certain cells that facilitate movement, such as in the case of dinoflagellates like Amyloodinium, for example.

Flux: A continued flow or movement.

Food chain: A series of organisms that represent the sequence of food from producers to ultimate consumers.

Free-living: Independent, as applied to an organism; opposite of parasite.

Gallons per Hour (GPH): The number of gallons that will move through a new device at zero head height in one hour.

Genus: A taxonomic category containing subgenera and species.

GH: General, total or permanent hardness; a measurement of the overall concentration of calcium, magnesium and other ions. Measured in degrees, with one degree equal to 17.9 ppm. The higher the degrees, the harder the water.

Gradients: A system of relationships within an organism or its environment which involves changes of increasing or decreasing magnitude with reference to metabolism, growth, pressure, energy forms, or other physical and physiological parameters and activities.

Granuloma: Refers to a grouping or aggregation of cells usually of a type associated with chronic inflammation, such as in the case of Mycobacteriosis. Considered to be a definitive symptom, granulomas can be seen in liver and kidney tissue of fish that have been exposed to Mycobacterium sp. infections.

Grass shrimp: A species of small, transparent shrimp often sold for freshwater aquariums and as food for other fish; also called ghost shrimp. There are species in both freshwater and marine environments.

GTP: Guanosine triphosphate.

Habitat: The specific place where an organism lives; a region characterized by particular environmental factors.

Hardness: A term usually limited to freshwater describing the total concentration of certain minerals in the water, e.g., water high in calcium and magnesium.

Hemoglobin: The oxygen-carrying pigment found in red blood cells. When bound with oxygen, it forms oxyhemoglobin, which gives blood its bright red coloration.

Herbivore: An organism, which consumes vegetable matter as its primary food source. Tangs can be considered herbivorous, since their diet consists mainly of algae.

Heterotroph: An organism that cannot derive its food from inorganic compounds. A heterotroph is capable of consuming many organic substances, and may rely on autotrophs or other heterotrophs for their food.

HLLE: Head and Lateral Line Erosion. It is speculated that many things, such as exposure to heavy metals and free electromagnetic fields, as well as vitamin and chemical deficiencies, whereby pigmentation and epithelium fades or appears to be eroded, can cause this condition.

Holistic: The idea or concept to view things in relation to a whole entity or as complete systems as opposed to analyzing things as just a series of parts.

Homeostasis: A steady-state; consistency of a balanced environment or condition of an organism.

HUFA: Highly Unsaturated Fatty Acids

Husbandry: The careful management of resources.

Hydrogen Peroxide: A chemical compound consisting of hydrogen and oxygen, with a chemical formula of H2O2. Hydrogen peroxide, when added to water, disassociates to form water and oxygen, and is therefore helpful in adding oxygen to an aquarium during power outages.

Hydrolyzed: Water as a reacting agent breaks other compounds into parts.

Hydronium ion: A water molecule with an extra hydrogen atom (H+). The measurement of which is a pH unit.

Hydrosphere: The water environment of the Earth. Usually thought of as the oceans of the planet.

Hydrometer: A calibrated instrument used for measuring the specific gravity of a liquid. Constructed of both glass and plastic, they are typically standardized at a specific temperature, and their accuracy is dependent on the relationship of the temperature of standardization in comparison to that of the solution being tested.

Hyperplasia: The enlargement of an organ or tissue due to an increase of constituent, although not abnormal cells.

Hypobromus Acid: A free-radical chemical compound (BrOH), which is formed when natural sea water (or, for that matter, artificial salt mixes), typically containing high concentrations of bromine, is exposed to ozone. It acts as an oxidizer, much like chlorine, and is detrimental to fish and invertebrates.

Hyposaline: A salinity lower than normal seawater. Hyposalinity conditions are sometimes used to combat certain ectoparasites, such as Amyloodinium, for example.

Hyphae: Filaments or hair-like structures associated with external fungal infections.

Hypoxemia: A condition, which is caused by an inadequate supply of oxygen.

Hypoxic: A condition of low oxygen tension or low oxygen content (availability).

Iatrogenic: Doctor-caused. Over-dosing with medications to the point where fish become adversely affected can be considered an iatrogenic condition.

Immunostimulant: A group of compounds or drugs, which enhance or increase a body's natural defenses against disease.

Inbreeding: The breeding of related individuals, such as brothers and sisters. Can cause abnormalities and defects.

Induction: The chemical influence of a group of cells in modifying the pattern of differentiation in other, associated cells.

In situ: In the normal form or normal position.

Integument: The outer covering of the body.

Intermediary metabolism: A term used to describe the chemical reactions involved in the transformation of food molecules into essential cellular building blocks.

Ion: An electrostatically charged atomic particle.

International Marine Alliance: An organization, formed in 1985 by Peter Rubec. Originally, its purpose was to combat the use of cyanide in the collection of marine fish. It now focuses on a broader picture, in an attempt to reform the trade in all reef species, and at the same time, promote reef conservation.

Invertebrate: An animal without a backbone, e.g., corals, crabs, anemones, clams, and shrimp.

Kinetics: Physical motion or activity.

Krebs cycle: Citric acid cycle. Biochemical explanation for organic energy.

Lamella: Thin plate or scale; gill tissue found in teleost fish.

Laminar Flow: Smooth flow in parallel layers without turbulence.

Larva: A pre-adult form that hatches from an egg and often leads a different life to that of the adult organism.

Lateral: Referring to the sides of an animal.

Lateral Line: A sensory canal running along the sides of the fish. The lateral line of fish senses pressure differences to warn fish of potential disturbances in its environment.

Lipid: Any fat-like compound.

Live Rock: Rock taken from the sea that is encrusted with living organisms, e.g., algae and invertebrates.

LPS Coral: Large Polyped Stony coral, e.g., Bubble coral, Euphyllia, and Favia.

Malady: A disease or cause of a diseased condition.

Mantle: The membrane lining the respiratory cavity of mollusks.

Marine Aquarium Council: An organization, formed by Paul Holthus, in conjunction with the World Wildlife Fund, the World Bank, the Packard Foundation and many other environmentally involved constituents for the conservation of coral reefs and other marine ecosystems by creating standards and certification for those engaged in the collection and care of ornamental marine life from the reef to aquarium.

Medusa: The jellyfish stage of a coelenterate.

Melanin: The yellow, brown or black pigment, which gives skin, eyes and fins their color, produced by cells known as melanocytes.

Mesoglea: The jelly-like layer between epidermis and gastrodermis in the Coelenterata and Ctenophora.

Metabolic: Involving metabolism.

Metabolism: The biochemical or inorganic energy changes that occur within a living organism, its cells or its organelles; involved in various specialized life activities.

Metamorphosis: A change in form or physical shape.

Microbial mediation: Microbial cells and colonies changing their environment using physical constituents like substrate, nutrients and solvents gradients to live and reproduce. Microscopic organisms inhabiting a particular habitat.

Micrometers: A measurement of length that equals one millionth of a meter.

Microzone: A microscopic portion of a particular habitat, e.g. surface-to-water interface.

Mineralization: Production of inorganic nitrogen compounds, such as ammonia by bacteria.

Mitochondria: Cytoplasmic organelle involved in cellular respiration; the power plant that produces the energy unit ATP.

MS-222: Tricaine methanosulfonate. A chemical compound used to put a fish to sleep in order to perform an otherwise stressful procedure. Finquel® is a registered trade name for this compound.

Mysid Shrimp: A member of the crustacean Order Mysidacea and a highly nutritional food source widely used in the trade as fish food.

Nitrate (NO3): A nitrogen-laden bi-product of the reduction of fish wastes by beneficial Nitrobacter bacteria. It encourages alga growth and may be toxic to some fish and invertebrates.

Nitrite (NO2): A nitrogen-laden bi-product of the reduction of fish wastes by beneficial Nitrosomonas bacteria. It encourages alga growth and at low levels is toxic to most fish and invertebrates.

Nitrogenase: Enzyme used by nitrogen-fixing bacteria to catalyze the reduction of molecular nitrogen to ammonia. Measurement of nitrogenase has been used to quantify nitrogen cycle activity.

N:P: A ratio of measured nitrogen and phosphorous in an environment.

Nucleus: A definite body within a cell; containing chromatin and surrounded by a double membrane.

Nutrient: Various inorganic constituents taken from the environment by organisms and combined into organic compounds through the use of solar or metabolic energy via the processes of photosynthesis and biosynthesis.

Nori: A form of seaweed, which has been dried and processed to form flat sheets, originally used as an ingredient in sushi and other oriental foods. It has been used lately to feed herbivorous fish, and is helpful in providing them with the vegetable matter, which they require.

Obligate: Limited to or restricted by a particular environment.

Oligotrophic: Low in available plant nutrients, minerals, and organisms and rich in oxygen at all depths.

O:N: A ratio between oxygen and nitrogen in an environment.

Omnivore: Refers to the feeding habit of organisms, which are capable of deriving nutrients by feeding on many things.

Operculum: Bony gill cover.

Opportunistic: That which takes advantage of opportunities. Opportunistic bacteria will seek areas of interruption or injuries to a fish's slime coat or epithelium, causing secondary infections.

Organ: Group of cells or tissues functioning as a unit.

Organelle: A specialized structure in a cell that performs a special function, e.g., mitochondria.

Organism: An individual living thing.

Osmoregulatory: Possessing the ability to regulate osmosis.

Osmosis: Molecular diffusion through a semi permeable membrane.

Osmotic Shock: Stress to an organism due to a solute/solvent change in its environment.

Oxic: The condition or environment of having sufficient available oxygen.

Oxidation: The chemical process by which oxygen is added to an element or compound, which changes the general nature of the element or compound, such as what occurs in the process of corrosion, for example.

Oxidation Reduction Potential (ORP): A measure of the effectiveness of the redox process using the minute electrical charge it generates in millivolts (mV) with an Oxidation Reduction Potential meter.

Ozone: An unstable poisonous gas that can be used for killing disease-causing organisms and/or improving water quality.

Oxygenic: A condition of an environment that allows oxidation, as in combustion of fuels or nutrients, to occur easily.

Parasite: An organism that lives on or in the body of a host animal or plant and from which it obtains nourishment, often detrimental to the host.

Parts Per Million (ppm): A measurement in chemistry to quantify the number of elements or constituents per a known volume.

Pathogen: An agent that causes disease.

Pathogenic: That, which is disease producing.

Pectoral Fin: Situated on each side of the body in fishes, behind the operculum.

pH: The logarithm of the reciprocal of the H+ ion concentration.

Photoautotrophs: Organisms that use light energy to synthesize organic compounds from inorganic substances, e.g., algae.

Photoperiod: Day length; period of time something is exposed to light.

Photosynthesis: Synthesis with energy from light, specifically the synthesis of carbohydrates by green plants in the presence of sunlight.

Photosynthesis respiration: There is a series of reactions in photosynthesis that do not use light - sugar is consumed, oxygen is consumed, and carbon dioxide is assimilated. A part of the 'dark reaction' the consumption of oxygen and/or production of carbon dioxide is usually a determination of respiration. This is particularly an important occurrence in plants producing fatty acids and proteins.

Phylum: A major group of animals or plants.

Phytoplankton: Microscopic plants that form part of the plankton.

Pico: Very small as in picoplankton; trillionth; smaller than micro.

Piscivore: A fish or other animal, which consumes fish as a food source.

Plenum: An empty or void space.

Polyp: The hydroid stage of a coelenterate.

Polysaccharide: A large molecule formed by condensation of many molecules of sugar. Nitrifying bacteria form a 'sugar-based glue' (polyglucosaccharide), which is used to affix the bacteria to its home sites.

Poikilothermic: An organism, whose internal temperature varies with that of its environment, such as fish. Poikilotherms are sometimes referred to as 'cold-blooded' although this is somewhat inaccurate. Other than birds and mammals, most animals are considered Poikilothermic.

Pore water: The minute area around sand particles and substrate material that bacteria attach themselves to and an active region of diffusion for all elemental components of energy flow and nutrient cycling.

Predator: An animal that hunts to catch food.

Primary production: Use by algae or plants of inorganic nitrogen to produce the nutrient ammonia.

Procaryotic cell: A cell lacking a definite nucleus and other double membrane organelles.

Prophylactic: Refers to a procedure, drug or piece of equipment used to prevent disease.

Protein: A large organic compound made up of amino acids.

Protozoan: An organism belonging to the Protozoa, which consists of a single cell. It constitutes the simplest and most primitive type of animal.

Protozoacide: A drug or chemical compound used in the treatment of protozoan disease organisms.

Pseudopodia: From the roots "pseud(o)" (false), and "podia" (foot), meaning false foot or appendage.

Putrification: A noun, which can be defined as the act of putrefying to make rotten.

Radicals: A group of atoms which acts as a unit in chemical reactions. Often the radical carries a very reactive and unstable electron charge or valence.

Reagent: A substance that has a known reaction to a given chemical or given water condition.

Redox: Applies to a sequence of chemical events in which elements/compounds transfer and/or rearrange positive and negative electrons. Elements/compounds that want to gain an electron are called reduction agents and have a negative charge. Elements/compounds that want to give up an electron are called oxidizing agents and have a positive charge. A pH dependent index of the chemical oxidizing potential.

Red Tide: An occurrence in coastal waterways and shorelines where massive fish kills occur as a result of an increase of toxins released by algae, such as the dinoflagellates, Gymnodinium brevis.

Reduction: The process of reducing or decreasing something, as in electron transfer to give away or transfer electrons to another element or compound; the lowering of toxicity in compounds through oxidation, such as the reaction, which occurs when ammonia is oxidized and reduced to nitrite, for example.

Respiration: In cells, the oxidation of foods; all steps involved in taking in oxygen and giving off carbon dioxide.

Reverse Osmosis (RO): A method to purify water.

Rhizoid: A root-like structure lacking vascular tissue.

Rhizome: An underground stem.

RNA: Ribonucleic acid; involved in protein synthesis.

RNA and protein: The site of protein synthesis.

Root: The plant organ whose primary functions are anchorage and absorption.

Salinity: The amount of salt (solute) dissolved in water (solvent). The density of salt in a volume of water. Applies to the unit of measure used to quantify the salt content of NSW.

Slough: To shed, usually mucus or epithelium (skin).

Sodium Bisulfate: A chemical compound with the composition Na2So4. It can be used for the temporary reduction of pH in solutions.

Solute: The substance dissolved in a liquid (solvent).

Sorption: The act or process of uptake, either on the outside or inside or both.

Species: A group of similar organisms; the basic unit in a classification; a group of interbreeding (or potentially interbreeding) individuals isolated reproductively from other such groups.

Specific Gravity: A ratio of relative density as given by the weight of a particular volume of a substance compared to that of an equal volume of water. Applies to the unit of measure used to quantify the salt content of artificially mixed seawater.

Spirulina: A blue-green algae (cyanobacteria), which is high in nutrients and other beneficial compounds. Spirulina is used in the formula of many foods for fish.

Sporangium: A spore producing structure.

Spore: A cell capable of developing independently into a new individual.

Sporogenesis: The production of spores; in the sporophyte this takes place by meiosis.

SPS Coral: Small Polyped Stony coral, e.g., Acropora.

Substrate: The substance acted upon by an enzyme. Sometimes referred to as the gravel or sand/sediment in an aquarium.

Substratum: The material upon which an organism lives.

Surficial interface: The transition zone between sediment (substrate) and water in aquatic or marine environments. Often it is measured by its gradient between plentiful oxygen and decreased oxygen.

Sump: Lowest region or reservoir in a plumbed aquarium system.

Taxonomy: The study of the classification of all living organisms into the Linnaean classification system using Latin names and nomenclature rules.

Territorial behavior: Behavior associated with defense of an area by an animal.

Tissue: A group of cells having the same function and structure.

Total alkalinity: The quantity of base (hydroxyl ion, OH-) present in water, usually measured in milligrams per liter, or parts per million of the important and commonly present base named calcium carbonate (CaCO).

Trace Elements: A minor constituent element found naturally in seawater that may be required for certain biochemical functions.

Trophic level: A group of organisms occupying the same level in a food chain.

Tubercle: Modified thorn-like scale.

Ubiquitous: Always or ever-present. Some experts feel disease organisms are ubiquitous to our tropical fish and within their aquarium homes.

Unilateral: Having or affecting only one side.

Valence state: The condition of an atom or element denoting its combining power with other elements. This combining power ultimately determines the ability to form bonds or relationships with other atoms and molecules.

Vascular: Vessels that carry or circulate fluids through an organism.

Ventral: Underside of the body. Opposite the dorsal.

Virus: Subcellular biological entity of protein and nucleic acid capable of reproducing only in living cells.

Vitamin: An essential dietary supplement; not used as a source of energy but required in enzyme systems.

Wattage: The amount of energy the device consumes.

Water Change: The removal of a percentage of aquarium water and its replacement with freshly prepared, non-polluted water to dilute the buildup of waste compounds and elements, and replace lost trace elements.

Warranty: Expressed in terms as the amount of time during which the company will replace or repair the item for free.

Zeolite: Also known as clinoptilolite, zeolite is naturally occurring form of aluminosilicate. It possesses a large interstitial pore space, which makes it highly absorptive of gasses, such as ammonia.

Zoology: The science of animal life.