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Dario dario (HAMILTON, 1822)

Scarlet Badis

SynonymsTop ↑

Labrus dario Hamilton, 1822; Badis dario (Hamilton, 1822); Badis badis bengalensis Tomey, 1999


Dario: derived from the specific epithet of the type species, dario, which in turn is from its Bangla name, Darhi.

dario: as above.


Order: Perciformes Family: Badidae


Appears to be restricted to tributary systems draining into the Brahamaputra River in parts of West Bengal and Assam states, India although it may also range into Bhutan.

When Hamilton described this species he did so without preserving any specimens, therefore to avoid confusion with similar-looking congeners.

Kullander and Britz (2002) designated a neotype which was collected from as close to the original type locality as possible, i.e., near the town of Raimana in western Assam.

The neotype locality is ‘Janali River, Raimana, 26°39’00″N, 89°58’00″E, Brahmaputra River drainage, Kokrajhar District, Assam, India’.


Typically inhabits shallow, clear water streams with sand or gravel substrates and dense growths of marginal and/or aquatic vegetation.

At one locality the macrophyte assemblage included members of Hygrophilia, Limnophila, Ottelia, Rotala and Vallisneria.

It occurs sympatrically with Badis blosyrus and B. kanabos at the neotype locality.

Maximum Standard Length

One of the smallest percoid fishes known. Males grow to around 20 mm and females 13 mm.

Aquarium SizeTop ↑

A pair or single male with multiple females can be housed in an aquarium with base dimensions of 45 ∗ 30 cm or more.


Best-maintained in a well-structured arrangement with plenty of cover.

A soft substrate is preferable although fine-grade gravel is acceptable, while ideal plants include Cryptocoryne spp. or those that can be grown attached to the décor such as Microsorum, Anubias, or Taxiphyllum species.

The latter is particularly useful as it’s also an ideal spawning substrate, and driftwood branches, floating plants and leaf litter can all be used as well.

Water Conditions

Temperature18 – 26 °C

pH6.5 – 8.5

Hardness18 – 268 ppm


Dario species are micropredators feeding on small aquatic crustaceans, worms, insect larvae and other zooplankton.

In captivity they should be offered small live or frozen fare such as Artemia nauplii, Daphnia, grindal, micro-, and banana worm.

They’re noted as somewhat shy, deliberate feeders (see ‘Behaviour and Compatibility’) and it’s also important to note that all badids develop issues with obesity and become more susceptible to disease when fed chironomid larvae (bloodworm) and/or Tubifex so these should be omitted from the diet.

Behaviour and CompatibilityTop ↑

Not a gregarious fish as such and rival males can be very aggressive towards one another, especially in smaller tanks.

In these cases only a single pair or one male and several females should be purchased but in roomier surroundings a group can coexist provided there is space for each male to establish a territory and plenty of broken lines of sight.

Thoughtful placement of caves and boundaries can help tremendously in this respect so don’t be tempted to cluster all available spawning sites in one area of the tank, for example.

If you do intend to house it in a community tankmates must be chosen with care.

It’s slow-moving with a retiring nature and will easily be intimidated or outcompeted for food by larger or more boisterous tankmates.

Peaceful, pelagic cyprinids such as MicrodevarioBoraras, Trigonostigma or smaller Rasbora species make good choices as do diminutive loaches such as some members of the genus Petruichthys.

Sexual Dimorphism

This species is very easy to sex but often only males are traded.

Females are smaller, less colourful (they do not have any red or blue pigmentation on the flanks and only indistinct bars or none at all) and possess a noticeably shorter, stumpier-looking body profile then males.

In addition, males develop extended pelvic, dorsal and anal fins as they mature.


Substrate-spawner forming temporary pair bonds.

Other fishes are best omitted if you want to raise good numbers of fry, although in a mature, well-furnished community a few may survive to adulthood.

Either a single pair or a group of adults can be used but if using multiple males be sure to provide each with space to form a territory with around 30 cm² per individual adequate.

One male will usually become dominant meaning the others will not be involved in breeding.

Water parameters should be within the values suggested above and the fish conditioned with plenty of live and frozen foods.

As they come into breeding condition males will begin to form territories and display courtship behaviour alongside an intensified colour pattern.

This can be prolonged for several days with the female often being chased away then courted again minutes later.

The male will make a non-aggressive approach towards the female and appear to ‘invite’ her into the centre of his territory, and if ready to spawn she will follow.

The act itself is over in just a few seconds with eggs being scattered in a random fashion on the underside of a solid surface such as a plant leaf.

Post-spawning the female is ejected and the male takes sole responsibility for the territory.

If you want to maximise the numbers of fry raised now is the time to either remove the medium to a container containing water from the spawning tank or the adults as the fry will be preyed upon once hatched.

The incubation period should be 2-3 days after which the fry may need up to a week to fully absorb the yolk sac.

They are very small indeed and will require an infusoria-type diet until large enough to accept microworm, Artemia nauplii, and suchlike.

NotesTop ↑

In the aquarium hobby this species is among the more well-known badids and is an increasingly popular choice for ‘nano’ aquaria.

It is easily told apart from congeners since it’s the only species in which males possess a series of seven iridescent blue vertical bars on the flanks.

D. dario can be further distinguished from D. dayingensis by absence (vs. presence) of palatine teeth in the upper jaw, 8½ (vs. 9½) scales in the transverse row, and presence (vs. absence) of distinct pre-, post-, and supraorbital stripes.

It differs from D. hysginon in absence (vs. presence) of an anguloarticular lateralis canal, and from both D. hysginon and D. dayingensis by possessing 13-14 (vs. 15-16) dorsal-fin spines and lacking (vs. possessing) both infraorbital bones and a black spot in the anterior portion of the dorsal-fin.

You may see it referred to as Badis badis bengalensis or B. bengalensis which is a result of an erroneous ‘description’ published by a hobbyist magazine in 1999.

Dario currently contains five species, of which four are considered miniature species since they do not exceed 26 mm in standard length (SL).

The fifth, D. urops, not only grows larger, to at least 28.0 mm SL, but occurs in southwestern India whereas the others are native to the Brahmaputra, Meghna, and Ayeyarwaddy river systems in northern India, Myanmar, and southwestern China, and this raises interesting questions regarding their biogeography.

In addition, D. urops lacks some diagnostic characters of Dario and thus may represent the sister group to other members of the genus, though this hypothesis remains to be tested.

Prior to 2002 the family Badidae included just five species but an extensive revision paper published that year contained descriptions of ten new species along with the genus Dario of which the former Badis dario was designated type species.

Dario is most easily distinguished from Badis by the small adult size of member species, predominantly red colouration, more extended first few dorsal rays and pectoral fins in males, straight-edged (vs. rounded) caudal-fin, lack of visible lateral line and less-involved parental behaviour.

Badids have historically been considered members of the families Nandidae or Pristolepididae and it was not until 1968 that Barlow proposed a separate grouping for them.

They share some characteristics with anabantoids, nandids and channids, perhaps most notably the typical spawning embrace in which the male wraps his body around that of the female.

More recent studies have concluded that this procedure is an ancient trait inherited from a common ancestor to all these families.

All BadisDario and Nandus species were found to share a uniquely bifurcated (split) hemal spine on the penultimate vertebra and this may provide evidence that the group is monophyletic (Kullander and Britz, 2002).

The family Nandidae is currently restricted to include only Nandus species and it’s separated from Badidae by differences in morphology and egg structure with their phylogenetic relationships yet to be studied in detail.


  1. Hamilton, F., 1822 - Edinburgh & London: i-vii + 1-405
    An account of the fishes found in the river Ganges and its branches.
  2. Britz, R. and S. O. Kullander, 2013 - Zootaxa 3731(3): 331-337
    Dario kajal, a new species of badid fish from Meghalaya, India (Teleostei: Badidae).
  3. Britz, R., A. Ali and S. Philip, 2012 - Zootaxa 3348: 63-68
    Dario urops, a new species of badid fish from the Western Ghats, southern India (Teleostei: Percomorpha: Badidae).
  4. Kullander, S. O. and R. Britz, 2002 - Ichthyological Exploration of Freshwaters 13(4): 295-372
    Revision of the family Badidae (Teleostei: Perciformes), with description of a new genus and ten new species.
  5. Rüber, L., R. Britz, S. O. Kullander and R. Zardoya, 2004 - Molecular Phylogenetics and Evolution 32(3): 1010-1022
    Evolutionary and biogeographic patterns of the Badidae (Teleostei: Perciformes) inferred from mitochondrial and nuclear DNA sequence data.

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