Capable of being erected, raised, or elevated, e.g. an erectile fin spine.

Chromatophore containing carotenoid pigment and thus having red or orange colour.

Of fishes, shaped like a pike.

Unpaired skull bone located on the anterior part of the neurocranium and forming a section of the nasal cavity.

Light, spongy bone of the skull located between the orbits and forming part of the eye socket and nasal cavity.

The study of animal behaviour, particularly in the natural environment.

Branch of linguistics concerned with the origin and development of words. Used in taxonomy when referring to the basis and meaning of a scientific name.

A single-celled or multicellular organism possessing cells containing a membrane-bound nucleus.

Capable of existing over a wide range of water depths.

Dwelling on the bottom of a water body over a wide range of depths.

Of aquatic organisms, able to tolerate a wide range of salinity. Opposite of stenohaline.

Of organisms, able to tolerate a wide range of temperatures.

Having water rich in nutrients, thus promoting the growth of plants, especially algae.

Hypertrophication; process by which addition of artificial or natural substances, such as nitrates and phosphates, to a body of water increases the concentration of dissolved nutrients, this in turn stimulating the growth of aquatic plant life, especially phytoplankton, and typically resulting in depletion of dissolved oxygen. Negative effects include reductions in populations of fishes and […]

Abbreviation of the Latin ex grege, meaning ‘from the herd, of the group’. Sometimes used between the generic and specific parts of a binomial name when the precise species is not known but the organism can be identified as belonging to a named group of species.

The study or maintenance of an organism or groups of organisms outside of the natural habitat

Process of protecting and maintaining an organism outside its natural habitat, e.g., in a zoo or relocation project.

A name unavailable for purposes of zoological nomenclature under provision of the ICZN code or because of a disclaimer.

Abnormal bulging of the eye from the orbit commonly referred to as 'pop eye' in aquarium literature and resulting from excessive accumulation of fluid or gases at the back of the socket. Not a disease but a secondary sympom of some other infection or physical issue.

External skeleton, often forming a hard, shell-like outer covering typical in insects, crustaceans and some molluscs. Usually chitinous but may also be composed primarily of calcium carbonate or silica.