The term dither fish refers to an arbitrary group of aquarium fish used by cichlid keeping aquarists to reduce innate timidity in some species of cichlids (Barlow, 1967). The technique relies on the ability of cichlids in an aquarium to use the behaviour of other fish species as a measure of environmental security (Loiselle, 1979). Good dither fish are typically schooling species such as Danio spp., barbs and some tetra species. Genera Cichlids (pronounced “sick-lids”) are a fishes from the family Cichlidae in the order Perciformes. ... Species of Danionin Danio Danio albolineatus Danio abolineatus var pulcher Danio abolineatus var tweediei Danio choprae Danio dangila Danio feegradei Danio kerri Danio kyathit var spotted Danio kyathit var striped Danio meghalayensis Danio nigrofasciatus Danio roseus Danio rerio Danio rerio var frankei Danio sp aff kerri Danio sp aff kyathit... Look up tetra- in Wiktionary, the free dictionary. ...

References

• Barlow, GW (1968) Dither--a way to reduce undesirable fright behavior in ethological studies. Z. Tierpsychol 25:315-318.
• Loiselle, PV (1979) On dither fish. Freshwater and Marine Aquarium Magazine November:30-34, 76-79 (also online).