Our journal suffers from the on-going malaise of being chronically short of beginners’ articles. Hence the “for Dummies” series to try to balance the article list with some works for our new members. But even the “for Dummies” had necessarily introduced a lot of terminology that is not in everyday use. And of course, the terms used in some of the more advanced articles may be completely unfamiliar to the novice. So here is a glossary of some of the terms that have appeared in The Calquarium in the last year or so to serve as a review of those introduced in the “for Dummies”, and as an explanation of those used in the advanced articles.
Acid: indicative of a pH below 7 or a chemical that lowers pH.
Acidity: a measure of water’s ability to resist upward changes in pH when a base is added.
Alkali: a chemical that raises pH, also known as a base.
Alkaline: indicative of a pH above 7.
Alkalinity: a measure of water’s ability to resist downward changes in pH when an acid is added. Sometimes referred to as “buffering”.
Andropodium: a modified anal fin found on the males of the half-beak fishes that is used in the transfer of sperm to the female.
Anion: negatively charged ion, that is, an ion that has one or more extra electrons over protons.
Anabantoids: also known as the labyrinth fishes. Those fish that are members of the order Perciformes and posses a labyrinth organ, which is a delicate network of blood-vessel inter-laced bones above the gills. The labyrinth organ is used to absorb oxygen from the air. The fish gulps air from the surface to fill the labyrinth organ. These fishes include the bettas, gouramis, and climbing perches. The anabantoids are sometimes incorrectly called the anabantids, a term that should only be used for the climbing perches of the family Anabantidae, and so would not include the bettas and gouramis, which are members of the family Belontiidae.
Base: a chemical that raises pH, also known as an alkali.
Benthic: bottom surface dwelling, as in the benthic invertebrates that encrust live rock.
Binomial Nomenclature: the species-naming convention invented by Carl von Linné where species are given a two-part name. The first part is the genus name, which must be unique, as for example the genus name Cyrtocara. The second part is the species name, which must be unique within the genus in question, but may be used in other genera as well. The combination of genus plus species must however be unique. For example the genus name Cyrtocara and the species name moorii combine to form the scientific name Cyrtocara moorii, but the species name “moorii” is also used in Tropheus moorii. Note that by convention the genus name is always capitalized and the species name is always entirely lower case, and the complete name is always italicized.
Calcitic rocks: composed largely or solely of a calcium compound, such as calcium sulphate, calcium phosphate, and most commonly calcium carbonate. These rocks may have a biological origin (fossilized coral skeletons, mollusk shells, etc.) or be the result of direct chemical precipitation of calcium compounds from water. Waters in contact with these rocks are usually hard and alkaline, with a pH near 8.2.
Cation: a positively charged ion, that is, an ion that has one or more fewer electrons than protons.
Chisawasawa: a genetically related group of sand-feeding cichlids from Lake Malawi.
Cichlids: members of the family Cichlidae. These include the angelfish, discus, and numerous other species from Central and South America, Africa, India, and Madagascar.
Cladistics: a method of taxonomic classification that puts sole emphasis on the evolutionary relationships between organisms.
Class: a taxonomic classification between phylum and order. Different orders may be grouped into a single class, as for example, both the order Perciformes (the perch-like fishes) and order Siluriformes (the catfishes) are in the class Osteichthyes (the bony fishes).
Congeners: individuals that are members of the same genus. For example, the members of species Pterophyllum altum and Pterophyllum scalare are congeners.
Conspecifics: individuals that are members of the same species.
Cyprinids: members of the family Cyprinidae. These include the carp, barbs, rasboras, danios, minnows, and loaches.
Family: a taxonomic classification between order and genus. Different genera may be grouped into a single family, as for example, both the genera Pterophyllum (the angelfishes) and Symphosodon (the discus) are in the family Cichlidae (the cichlids).
Genera: plural for genus.
Genus: a taxonomic classification between species and family. Different species may be grouped into a single genus, as for example, both the species Pterophyllum altum (the high-fin angelfish) and Pterophyllum scalare (the common angelfish) are in the genus Pterophyllum. The genus name is included in the binomial scientific name as the first (capitalized) word.
Gonapodium: a modified anal fin found on the males of the poecilid fishes that is used in the transfer of sperm to the female.
Gondwana: a supercontinent that existed during and immediately after the age of dinosaurs. Gondwana has since broken up into South America, Africa, Saudi Arabia, Antarctica, Australia, India, Madagascar, and New Zealand. Many fishes, for example the tetras (characins), are found in Gondwanan continents that are now separated by oceans, having evolved and spread before Gondwana was still (at least partially) whole.
Haplochromine: belonging to the large group of cichlids in or descended from the African cichlid genus Haplochromis. The haplochromine lineage.
Hardness: a measure of the concentration of multivalent cations in the water, mostly calcium and magnesium cations.
Interstitial: “between the grains” as in the interstitial invertebrates that live between the grains of live sand.
Ion: an atom with a net electrical charge resulting from an unequal numbers of protons and electrons.
Kingdom: highest level of taxonomic classification. Different phyla may be grouped to form a kingdom, as for example both the phylum Mollusca (the mollusks) and the phylum Chordata (the chordates) are in the kingdom Animalia (the animals).
Labyrinth Fish: see anabantoids.
Laterite: an iron-rich clay. It is often found in tropical areas, and can be used in as a potting medium for aquarium plants.
Laurasia: a supercontinent that existed during and immediately after the age of dinosaurs. Laurasia has since broken up into Eurasia and North America. Many fishes, for example the minnows (cyprinids), are found throughout the Laurasian continents, having evolved and spread before Laurasia broke up.
Live Rock: porous calcitic rock (usually coral skeletons) that are encrusted with benthic invertebrates, algae, and bacteria. Usually collected from the wild in the “rubble zones’ near coral reefs. Used in marine “reef” aquaria.
Live Sand: fine calcitic sand in which lives a population of bacteria and small invertebrates. Usually collected from the wild near coral reefs. Used in marine “reef” aquaria.
Mbuna: a genetically related group of rock-dwelling cichlids from Lake Malawi. Most are rather pugnacious but very colorful and can be kept among their own kind in an aquarium.
Neotropics: the New World tropics, referring to southern Central America and northern South America.
Order: a taxonomic classification between class and family. Different families may be grouped into a single order, as for example, both the families Cichlidae (the cichlds) and Chaetodonitae (the butterfly fishes) are in the order Perciformes (the perch-like fishes).
Ovivivaparous: bearing live young that are hatched from eggs held within the mother’s body.
pH: a measure of the “activation potential” of hydrogen cations in water. Measured with a number that is the negative of the base 10 logarithm of the molar concentration of hydrogen cations. Numbers above 7 indicate an alkaline pH, well numbers below 7 indicate a negative pH. A pH of 7 is neutral.
Phyla: plural for phylum.
Phylum: a taxonomic classification between class and kingdom. Different classes may be grouped into a single phylum, as for example both the class Mammalia (the mammals) and the class Osteichthyes (the bony fishes) are in the phylum Chordata (the chordates).
Peacocks: a genetically related group of haplochromine cichlids from Lake Malawi placed in the genera Aulonocara and Trematocranus.
Photosynthetic: using light to manufacture food, as do green plants.
Piscivore: fish eater.
Planktivore: plankton eater.
Poecilids: fish of the family Poecilidae, including the guppies, mollies, platies, and swordtails.
Rhizome: a thick central part of the root of many plants. Many plants can be propagated by cutting the rhizome in two and planting the two halves separately.
Sahul: the continent that existed when sea levels were lower during the ice ages. Sahul includes the landmasses of Australia, Tasmania, New Guinea, and many smaller islands, along with the now-submerged land bridges that connected them. The rainbowfishes a have a natural range that covers the tropical and sub-tropical parts of Sahul.
Scientific Name: the globally recognized unique name assigned to each species. See binomial nomenclature.
Softness: having little hardness. See hardness.
Species: the lowest order of taxonomic classification. All members of a sexually reproductive species are enough alike that no physical or behavioral barriers exist to keep them from naturally interbreeding.
Taxonomy: the scientific endeavor to classify living things according to their similarities, differences, and evolutionary relationships. Traditionally, taxonomists will group organisms into their kingdom, phylum, class, order, family, genus, and species (in order of increasing specificity).
Utaka: a genetically related group of open water, plankton-feeding cichlids from Lake Malawi.
Vivaparous: bearing live young that are nourished by the mother’s body before birth.