Results for “genera”

heredity

The passing of characteristics or traits from parent or ancestor to offspring or later generations; the sum of such inherited features or their characteristics.

hydrometer

Instrument used to measure the density of a liquid, normally in the form of specific gravity. Can be inaccurate should calcium deposits form on the swing arm, for example, and generally less reliable than a refractometer.

Mollusca

Large, highly diverse invertebrate phylum. Members are difficult to define but generally possess a soft, unsegmented body, and often a shell or shell-like structure secreted by a mantle. Includes all bivalves, cephalopods, and gastropods.

pH

Measure of the acidity or basicity of an aqueous solution. Pure water is said to be neutral, with a pH around 7.0, solutions with pH of less than 7.0 acidic and greater than 7.0 basic or alkaline. Measured on a logarithmic scale of 0.0-14.0 whereby a change of a single unit represents a ten-fold increase in acidity or basicity/alkalinity, i.e., a solution with a pH of 4.0 is ten times more acidic than one of 5.0., and 100 times more acidic than one of 6.0. Some fishes require a relatively specific pH in aquaria, while others are more generalised, with the former requirement often-reduced in captive-bred examples.

Used in 397 profiles

phylogenetic species concept

Species concept based on the evolutionary relationships among organisms, specifically using common ancestry and shared evolutionary history to define species. Under this concept a species is essentially the smallest group of organisms that share a common ancestor and can be distinguished from other such groups via phylogenetic analyses. Each such grouping constitutes a distinct branch on an evolutionary tree. Subspecies tend not to be recognised and it is generally less restrictive than the biological species concept. Often abbreviated to PSC.

Used in 1 profile

pico aquarium

Tiny aquarium of arguable definition, but generally considered to have a volume between 2.5-5 US gallons (2.08-4.16 UK gallons; 9.46-18.93 litres). Also known as a pico tank.

plesiomorphy

In cladistics, a character or trait shared by two or more taxonomic groups but derived from a remote or much earlier common ancestral form and therefore cannot be used to define a clade. Also known as an ancestral state and generally appears at the base level of a cladogram.

Used in 2 profiles

polyphagous

Feeding on numerous food types; having a generalistic diet.

postoral pouch

A transverse, hollow, pouch-like structure opening anteriorly and located on the ventral surface, immediately posterior to the mouth, in some members of certain balitorid genera, e.g., Gastromyzon, Neogastromyzon.

Used in 13 profiles

processus dentiformis

Tooth-like projection in the middle of the upper jaw in certain loach genera which may fit into a notch in the lower jaw. Also referred to as dentiform process.

Used in 16 profiles

robust

Strong; vigorous; sturdy. Often used to describe the general body form of a fish.

Used in 246 profiles

salinity

General term for the salt concentration of water.

Used in 17 profiles

saprolegnia

Genus of aquatic fungi, some species of which attack fishes. Normally a secondary pathogen attacking previously damaged tissue and causing cellular necrosis alongside other epidermal damage. Generally visible as a whitish or greyish filamentous fungus and thus commonly referred to as cotton-wool disease.

sublacrymal groove

A fold or groove located between the lacrymal bone and rostral cap in certain fish genera.

Used in 13 profiles

total dissolved solids

Measure of the total concentration of both organic and inorganic, microscopic particles suspended in a given liquid. Usually applied only to freshwater systems and measured using a conductivity or total dissolved solids meter with results expressed in units of mg per unit volume of water (e.g., mg/L) or parts per million (ppm). Soft water with low pH generally has low levels of total dissolved solids whereas harder water with higher pH tends to contain correspondingly increased concentrations. Often abbreviated to TDS.

Used in 2 profiles

urostyle

Upturned, posterior tip or backwardly-orientated process of the lower vertebral column, generally comprised of fused vertebrae; series of bones articulating with the last true vertebra; usually included when counting vertebrae.

Used in 8 profiles