The natural home or environment of an organism.

Small, motor-driven, type of external filter that literally hangs over the edge of the aquarium. Unsuitable for larger aquaria and often abbreviated to HOB or HOT (hang on tank).

Wetland ecosystem of which most are located in northeast Bangladesh. The typical form is that of a bowl or saucer-shaped depression and the core haor area is surrounded by hills of the Indian states of Meghalaya to the north, Tripura and Mizoram to the south, and Assam and Manipur to the east. The area is known locally as the ‘Haor’ or ‘Sylhet’ basin and floods extensively […]

Water containing high concentrations of mineral salts.

Shaped like the head of a spear.

Severe physical condition relatively common to certain fishes in captivity and also known as hole-in-the-head. Sometimes attributed to protozoan parasites of the genus Hexamita or an autoimmune disorder though these theories remains unconfirmed. Certainly associated with and exacerbated by poor water quality and/or nutrition, however. Initially manifests itself as small lesions, normally on the head of an […]

Greatest vertical depth through the head.

Normally a straight-line measurement taken from the tip of the upper lip to the posterior edge of the operculum.

The distance between the two widest points of the head.

Tributary stream of a river close to or comprising part of its source.

Thermostatically-controlled device used to maintain constant water temperature in an aquarium or pond, also known as a heaterstat. Depending on design, may be installed submersed within the aquarium, sump or substrate (see heating cable) or inline with tubing attached to an external filter. Some types of the latter also have a heating element built in.

Length of flexible cable buried under the substrate in an aquarium and used to maintain constant water temperature. Also popular in planted aquaria due to the associated circulation of water within the substrate which aids in nutrient exchange between plant roots and the surrounding environment.

An organism whose diet consists almost exclusively of vegetable matter.

Feeding on plants.

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

Animal or plant possessing both male and female reproductive organs.

Of or belonging to a different species.

An organism that cannot synthesise its own food and instead obtains nutrients from complex organic substances, usually animal or plant matter.

Genus of parasitic flagellates, some species of which inhabit the intestines of fishes. May cause head and lateral line erosion.

Series of ordered or groupings or rankings within a defined system. Taxonomy is a form of hierarchy as are the ranked social groupings typical of certain fish species. The latter form of social hierarchy is also known as a pecking order.