Coding system used to organise and refer to unidentified catfishes, though not necessarily undescribed or distinct species, of the genus Corydoras. Works in tandem with the similar CW number system. The system was invented by German aquarist Hans-Georg Evers and first appeared in the magazine ‘DATZ’ but is now in popular use worldwide.

Composed of, containing, or characteristic of calcium carbonate, calcium, or limestone; chalky.

Cauldron-like volcanic feature usually formed by the collapse of land following a volcanic eruption, sometimes confused with volcanic craters. Often fill with water to form lakes.      

Resembling or having the form of a canine tooth

See external filter.

The hard upper shell of a tortoise, crustacean, or arachnid.

Measure of the alkalinity of water as dictated by the presence of bicarbonate and carbonate ions. Usually expressed as parts per million, milligrams per litre, or degrees (dKH) of which 1 dKH corresponds to 17.848 ppm. Sometimes used a synonym for, but not equivalent to, temporary hardness.

Arranged like a series of combs or the wire bristles on a wool card. In ichthyology used most commonly to describe the form and arrangement of teeth in certain species.

A scale possessing a distinct notch on the posterior margin.

Possessing a distinct ridge or keel.

Feeding on animals.

Any of a category of yellow to red pigments occurring naturally in plants and animals and including the carotenes and xanthophylls. Animals obtain carotenoids in their diets and they're known to enhance colouration in some fishes.

Dead and decaying animal flesh.

Specialised, toughened, elastic, fibrous connective tissue found in various parts of the body and forming the temporary skeleton in embryonic and very young fishes, but mostly lost as the majority of species mature. Retained throughout life in cartilaginous fishes.

A fish with a skeleton composed mainly of cartilage; major groups include sharks, rays and skates.

Migration of fishes from freshwater to the sea.

A dramatic, steep fall in a watercourse.

A collecting of water, especially rainwater.

The entire area drained by a given river or lake plus associated tributaries. Same meaning as drainage basin, river basin, watershed, etc..

Towards the poterior or caudal fin.