Results for “species”

crossbreed

An organism with parents of two different breeds, races, varieties, or species; the process involved in producing such an organism.

Used in 2 profiles

crustacean

Any member of the predominantly aquatic arthropod grouping Crustacea which currently contains almost 70,000 recognised species, including all crabs, lobsters, crayfish, shrimp, krill and barnacles. It's difficult to define their characteristics since the group is of arguable hierarchical status, generally regarded to represent either a Phylum or Subphylum.

Used in 421 profiles

CW number

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 C number system. The system was invented by Ian A. M. Fuller in reference to his website 'Corydoras World' but is now in popular use worldwide.

Used in 65 profiles

decapod

Any member of the crustacean order Decapoda, comprising species possessing 5 pairs of jointed, thorassic limbs such as crabs, crayfish, lobsters and shrimp. Also used historically in reference to molluscs of the Cephalopod superorder Decapodiformes, members of which have 8 short limbs plus 2 longer tentacles and include cuttlefish and squid.

deionisation

Purification process, often abbrevaited to DI, by which mineral ions are removed from water, usually via ion exchange over a specialised type of resin. The process does not remove non-ionic molecules thus organic cells such as bacteria tend to remain. Often used in conjunction with reverse osmosis to produce more-or-less pure water which normally requires a degree of remineralisation before being used in aquaria.

dentition

The arrangement, type, and number of the teeth in a particular species

Used in 60 profiles

depensation

Reduction in breeding population size leading to reduced fecundity in the overall population or stock of a species.

derived

Used in phylogenetics in reference to a character or character state not present in the ancestral form of a species; apomorphic.

Used in 190 profiles

description

Used in ichthyology in reference to a written description of a new species, usually in the form of a scientifically-published paper though many have been also appeared in aquarium literature, particularly in the late twentieth century. Also referred to as 'type description' or 'original description'.

Used in 283 profiles

dichotomous key

Species identification key comprising pairs of alternative choices arranged in a series of couplets, used commonly in ichthyological papers.

dimorphism

In biology, the occurrence within a species of two forms which differ distinctly from one another in one or more characters, e.g., colour pattern or morphology.

Used in 2 profiles

dioecious

Within a species, having the male and female reproductive organs in separate individuals.

dither fish

Fish or group of fish, typically inhabiting open water in the mid-to-upper water column, used by aquarists to reduce innate shyness in other species.

Used in 65 profiles

dorsal-fin

Median, rayed, unpaired fin located on the dorsal surface (back) of most fishes. Its main purpose is to prevent the animal rolling and enable it to turn sharply. Some species possess more than one dorsal fin, in which case the anterior one is referred to as the first.

Used in 860 profiles

drip acclimation

Method of acclimation used for sensitive fish species in which the animals are first placed into a clean bucket or other container before water is slowly dripped in by siphon from the aquarium into which they are to be introduced. Can be carried out using a purchased kit or home-made using a length of airline plus an airline clamp.

ecological niche

The specific position or function that an organism fills in an ecosystem.

Used in 77 profiles

ecotype

A distinct population of a species adapted to occupy a particular habitat due to localised natural selection.

egg scatterer

A species spawning above the bottom which scatters demersal eggs randomly.

Used in 81 profiles

Enchytraeus

Genus of annelid worm of which two species, E. albidus and E. buchholzi, are cultured by aquarists to use as fish food.

epibranchial organ

Present in some microphagous fishes and comprises a paired dorsal diverticulum located towards the posterior of the pharynx. In the majority of species it's divided into two sections by additional gill rakers which trap small food particles.