Danio
Encyclopedia
The Danio genus comprises many of the species of danionin
s familiar to aquarists. The common name "danio" is used for members of the genera Danio and Devario
.
, have now been reclassified into the Devario
genus. Also, Brachydanio is now a junior synonym
of Danio.
The following are varieties recognized in the aquarium trade but are not considered valid species.
Some undescribed species or varieties, which may be represented by recently described species above, include:
river
s and streams of Southeast Asia
, but many species are brightly colored, and are available as aquarium fish
worldwide. A number of the species, only recently discovered in remote inland areas of Myanmar, do not yet have scientific names.
They have two pairs of long barbels, and are generally characterised by horizontal stripes (with the exception of the glowlight danio
, panther danio
and black barred danio
which have vertical bars). They range from 4-15 cm (1.75-6 in) in length. They generally do not live for more than two to three years, and are probably annual fish in the wild.
In the wild, these fish consume various small aquatic insects, crustacean
s, and worm
s, as well as plankton
in the case of fry.
All of these fish are primarily surface feeders. They are omnivorous in the aquarium and will accept a wide variety of foods, though flake food is appropriate. Living in aquaria, live/frozen flaked foods are suitable, especially brine shrimp
and sinking tablets. Danios are voracious eaters; timid feeders may starve in community tanks with danios. When conditioning danios for breeding, it is advisable to feed them plenty of fresh foods.
Although boisterous and liable to chase each other and other fish, they are good community fish and will not generally attack each other or other fish, although they occasionally nip fins, more by accident than design; like most fish, they will eat eggs and any fish small enough to fit into their mouths.
They are best kept in a tank long enough for their active swimming, preferably with a current from a power filter (or at least airstone) as they often live in fast-flowing streams in the wild. Generally, this also results in them being subtropical with cooler temperatures. They are good jumpers, so a tight-fitting lid is recommended.
As a schooling fish, they prefer to be in groups of six or more. Danios prefer water with a pH
between 6.0 and 8.0 , hardness no more than 19.0 dGH
,a carbon hardness of 8 to 12 KH, and a temperature range of 68–80°F (18–24°C), the lower end of the temperature range is ideal.
, are far harder to spawn. All scatter their eggs over the substrate. The eggs are not adhesive, and hatch within two or three days. Eggs will be eaten enthusiastically unless protected by a layer of marbles or heavy substrate planting.
Hybrids between some Danio species have been bred; the young can be raised to maturity, but are sterile.
Danionin
The danionins are a group of small minnow-type fish belonging to the family Cyprinidae. Members of this group are mostly in the genera Danio and Devario. They are native to the fresh waters of southeast Asia. Many species are brightly coloured and are available as aquarium fish worldwide...
s familiar to aquarists. The common name "danio" is used for members of the genera Danio and Devario
Devario
The genus Devario comprises some danionins familiar to aquarists. Generally, they are larger fish than species of the genus Danio, they have short barbels , and generally have deeper bodies than Danio species, with species having vertical or horizontal stripes present...
.
Taxonomy
The name "danio" comes from the Bengali name dhani, meaning "of the rice field". The native Bangla name for the fish is anju. The species Danio rerio was first described in the early 19th century by Francis Hamilton, a surgeon working for the British East India Company. About a century later (1916), the genus was split; the larger species into Danio and the smaller species, such as D. rerio, into the new Brachydanio. In 1991, though, the two genera were recombined; most larger species formerly within the Danio genus, such as the giant danioGiant Danio
The giant danio is a tropical fish belonging to the minnow family Cyprinidae. Originating in Sri Lanka, Nepal, and the west coast of India, this species grows to a maximum length of 6 inches , making it one of the largest of the danionins...
, have now been reclassified into the Devario
Devario
The genus Devario comprises some danionins familiar to aquarists. Generally, they are larger fish than species of the genus Danio, they have short barbels , and generally have deeper bodies than Danio species, with species having vertical or horizontal stripes present...
genus. Also, Brachydanio is now a junior synonym
Synonym (taxonomy)
In scientific nomenclature, a synonym is a scientific name that is or was used for a taxon of organisms that also goes by a different scientific name. For example, Linnaeus was the first to give a scientific name to the Norway spruce, which he called Pinus abies...
of Danio.
Species
- Danio aesculapii S. O. KullanderSven O. KullanderSven Oscar Kullander is a Swedish biologist specialised in ichthyology.He primarily researches cichlids – notably the genus Apistogramma and the Cichlasoma-complex – and other tropical fresh water fishes....
& F. Fang, 2009 - Danio albolineatus (BlythEdward BlythEdward Blyth was an English zoologist and pharmacist. He was one of the founders of zoology in India....
, 1860) (Pearl danio) - Danio choprae HoraSunder Lal HoraSunder Lal Hora was an Indian ichthyologist.Famous for the Satpura Hypothesis, a zoo-geographical hypothesis proposed by him that suggests that the central Indian Satpura Range of hills acted as a bridge providing for the Malayan affinity of many Indian fauna and flora in the peninsula and the...
, 1928 - Danio dangilaDanio dangilaDanio dangila, the Moustached Danio is a fish, and is the largest of the true Danios at up to 6 inches. It gains its name from its particularly long barbels...
(F. HamiltonFrancis Buchanan-HamiltonDr Francis Buchanan, later known as Francis Hamilton but often referred to as Francis Buchanan-Hamilton was a Scottish physician who made significant contributions as a geographer, zoologist, and botanist while living in India.The standard botanical author abbreviation Buch.-Ham. is applied to...
, 1822) - Danio erythromicron (AnnandaleNelson AnnandaleThomas Nelson Annandale CIE was a Scottish zoologist, entomologist and anthropologist.The eldest son of Thomas Annandale, the regius professor of clinical surgery at the University of Edinburgh, Nelson was educated at Rugby School, Balliol College, Oxford, and the University of Edinburgh.Annandale...
, 1918) - Danio feegradei HoraSunder Lal HoraSunder Lal Hora was an Indian ichthyologist.Famous for the Satpura Hypothesis, a zoo-geographical hypothesis proposed by him that suggests that the central Indian Satpura Range of hills acted as a bridge providing for the Malayan affinity of many Indian fauna and flora in the peninsula and the...
, 1937 - Danio jaintianensis (Sen, 2007)
- Danio kerri H. M. SmithHugh McCormick SmithHugh McCormick Smith was an American ichthyologist and administrator in the Bureau of Fisheries.-Biography:...
, 1931 (blue danio) - Danio kyathitDanio kyathitDanio kyathit is a small, schooling species of fish in the family Cyprinidae, native to Myanmar. Described in 1998, it is closely related to the better known zebrafish or zebra danio, D. rerio.-Description:...
F. Fang, 1998 - Danio margaritatus (T. R. Roberts, 2007) (galaxy rasbora)
- Danio meghalayensis Sen & Dey, 1985
- Danio muongthanhensis V. H. Nguyen, 2001
- Danio nigrofasciatus (F. DayFrancis DayFrancis Day CIE was Inspector-General of Fisheries in India and Burma and an ichthyologist.He was born on 2 March 1829 Maresfield, Sussex, UK third son of William and Ann Day. He became the medical officer in the Madras Presidency, East India Company services in 1852.Francis Day was created a...
, 1870) (dwarf danio) - Danio quagga S. O. KullanderSven O. KullanderSven Oscar Kullander is a Swedish biologist specialised in ichthyology.He primarily researches cichlids – notably the genus Apistogramma and the Cichlasoma-complex – and other tropical fresh water fishes....
, T. Y. Liao & F. Fang, 2009 - Danio quangbinhensis (T. T. Nguyen, V. T. Le & X. K. Nguyen, 1999)
- Danio rerioDanio rerioThe zebrafish, Danio rerio, is a tropical freshwater fish belonging to the minnow family of order Cypriniformes. It is a popular aquarium fish, frequently sold under the trade name zebra danio, and is an important vertebrate model organism in scientific research.-Taxonomy:The zebrafish are...
(F. HamiltonFrancis Buchanan-HamiltonDr Francis Buchanan, later known as Francis Hamilton but often referred to as Francis Buchanan-Hamilton was a Scottish physician who made significant contributions as a geographer, zoologist, and botanist while living in India.The standard botanical author abbreviation Buch.-Ham. is applied to...
, 1822) (zebra danio) - Danio roseus F. Fang & KottelatMaurice KottelatDr. Maurice Kottelat is a Swiss ichthyologist.In 1976 he entered the University of Neuchâtel where he obtained his diploma in 1987. In 1980 he went to Thailand where he began his field research on Southeast Asiatic and Indonesian fresh water fish species...
, 2000 - Danio tinwiniDanio tinwiniDanio tinwini, commonly called Gold-Ring Danio, is a newly discovered species of Danio from Myanmar . It is also referred to as Danio sp. "TW02". It is a tiny gold fish whose body and fins are covered with blue spots. It has also been referred to as Danio sp "Ringlet" or Danio sp "Blue Ring"...
S. O. KullanderSven O. KullanderSven Oscar Kullander is a Swedish biologist specialised in ichthyology.He primarily researches cichlids – notably the genus Apistogramma and the Cichlasoma-complex – and other tropical fresh water fishes....
& F. Fang, 2009 - Danio trangi S. V. Ngô, 2003
The following are varieties recognized in the aquarium trade but are not considered valid species.
- D. abolineatus var. pulcher
- D. abolineatus var. tweediei
- D. rerio var. frankei
Some undescribed species or varieties, which may be represented by recently described species above, include:
- "Hikari"
- D. aff kyathit
- "KP01"
- "TW01"
Characteristics
They are native to the fresh waterFresh Water
Fresh Water is the debut album by Australian rock and blues singer Alison McCallum, released in 1972. Rare for an Australian artist at the time, it came in a gatefold sleeve...
river
River
A river is a natural watercourse, usually freshwater, flowing towards an ocean, a lake, a sea, or another river. In a few cases, a river simply flows into the ground or dries up completely before reaching another body of water. Small rivers may also be called by several other names, including...
s and streams of Southeast Asia
Southeast Asia
Southeast Asia, South-East Asia, South East Asia or Southeastern Asia is a subregion of Asia, consisting of the countries that are geographically south of China, east of India, west of New Guinea and north of Australia. The region lies on the intersection of geological plates, with heavy seismic...
, but many species are brightly colored, and are available as aquarium fish
Aquarium fish
In fishkeeping, species of aquarium fish vary with the water chemistry of the aquarium.For species of fish found in particular types of aquaria, see:*List of brackish aquarium fish species*List of freshwater aquarium amphibian species...
worldwide. A number of the species, only recently discovered in remote inland areas of Myanmar, do not yet have scientific names.
They have two pairs of long barbels, and are generally characterised by horizontal stripes (with the exception of the glowlight danio
Glowlight Danio
Glowlight danio is a small, schooling fish closely related to the popular zebrafish Danio rerio. This should not be confused with the GloFish , a trademarked brand of fluorescent zebrafish that appears to glow in the dark under a black light...
, panther danio
Panther Danio
The Panther Danio is a species of danio endemic to Myanmar. Before its description it was referred to as Danio species TW03...
and black barred danio
Black Barred Danio
A new species of danio discovered in Burma by Tin Win in 2005. The only one of the true danios not yet seen by hobbyists.Still awaiting a scientific name, temporarily referred to as Danio sp. TW01...
which have vertical bars). They range from 4-15 cm (1.75-6 in) in length. They generally do not live for more than two to three years, and are probably annual fish in the wild.
In the wild, these fish consume various small aquatic insects, crustacean
Crustacean
Crustaceans form a very large group of arthropods, usually treated as a subphylum, which includes such familiar animals as crabs, lobsters, crayfish, shrimp, krill and barnacles. The 50,000 described species range in size from Stygotantulus stocki at , to the Japanese spider crab with a leg span...
s, and worm
Worm
The term worm refers to an obsolete taxon used by Carolus Linnaeus and Jean-Baptiste Lamarck for all non-arthropod invertebrate animals, and stems from the Old English word wyrm. Currently it is used to describe many different distantly-related animals that typically have a long cylindrical...
s, as well as plankton
Plankton
Plankton are any drifting organisms that inhabit the pelagic zone of oceans, seas, or bodies of fresh water. That is, plankton are defined by their ecological niche rather than phylogenetic or taxonomic classification...
in the case of fry.
In the aquarium
The care of members of the genus Danio are rather similar and easily generalized. They are easy to keep.All of these fish are primarily surface feeders. They are omnivorous in the aquarium and will accept a wide variety of foods, though flake food is appropriate. Living in aquaria, live/frozen flaked foods are suitable, especially brine shrimp
Brine shrimp
Artemia is a genus of aquatic crustaceans known as brine shrimp. Artemia, the only genus in the family Artemiidae, has changed little externally since the Triassic period...
and sinking tablets. Danios are voracious eaters; timid feeders may starve in community tanks with danios. When conditioning danios for breeding, it is advisable to feed them plenty of fresh foods.
Although boisterous and liable to chase each other and other fish, they are good community fish and will not generally attack each other or other fish, although they occasionally nip fins, more by accident than design; like most fish, they will eat eggs and any fish small enough to fit into their mouths.
They are best kept in a tank long enough for their active swimming, preferably with a current from a power filter (or at least airstone) as they often live in fast-flowing streams in the wild. Generally, this also results in them being subtropical with cooler temperatures. They are good jumpers, so a tight-fitting lid is recommended.
As a schooling fish, they prefer to be in groups of six or more. Danios prefer water with a pH
PH
In chemistry, pH is a measure of the acidity or basicity of an aqueous solution. Pure water is said to be neutral, with a pH close to 7.0 at . Solutions with a pH less than 7 are said to be acidic and solutions with a pH greater than 7 are basic or alkaline...
between 6.0 and 8.0 , hardness no more than 19.0 dGH
DGH
Degrees of general hardness is a unit of water hardness, specifically of general hardness.General hardness is a measure of the concentration of metal divalent ions such as calcium and magnesium per volume of water...
,a carbon hardness of 8 to 12 KH, and a temperature range of 68–80°F (18–24°C), the lower end of the temperature range is ideal.
Breeding
Some species of Danio, such as the zebra danio, are among the easiest aquarium fish to breed. Other species, such as Danio kyathitDanio kyathit
Danio kyathit is a small, schooling species of fish in the family Cyprinidae, native to Myanmar. Described in 1998, it is closely related to the better known zebrafish or zebra danio, D. rerio.-Description:...
, are far harder to spawn. All scatter their eggs over the substrate. The eggs are not adhesive, and hatch within two or three days. Eggs will be eaten enthusiastically unless protected by a layer of marbles or heavy substrate planting.
Hybrids between some Danio species have been bred; the young can be raised to maturity, but are sterile.
See also
- DanioninDanioninThe danionins are a group of small minnow-type fish belonging to the family Cyprinidae. Members of this group are mostly in the genera Danio and Devario. They are native to the fresh waters of southeast Asia. Many species are brightly coloured and are available as aquarium fish worldwide...
s - full details of all fish related to the Danios, including those species known as danios which are no longer scientifically classified in the Danio genus - DevarioDevarioThe genus Devario comprises some danionins familiar to aquarists. Generally, they are larger fish than species of the genus Danio, they have short barbels , and generally have deeper bodies than Danio species, with species having vertical or horizontal stripes present...
s - details of the species within the genus DevarioDevarioThe genus Devario comprises some danionins familiar to aquarists. Generally, they are larger fish than species of the genus Danio, they have short barbels , and generally have deeper bodies than Danio species, with species having vertical or horizontal stripes present...