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Selasa, 14 September 2010

[uNGu]™ Fish : Badis badis - chameleon fish


Badis badis - Badis

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Breeding pair of <I>B. badis</I>, male on left.Young male with stress patterning.Another pair, male on left.Male guarding fry.
Breeding pair of B. badis, male on left.Young male with stress patterning.Another pair, male on left.Male guarding fry.
© Hayath© Hayath© Hippocampus-Bildarchiv© Hayath
Click here to scroll (4 images attached)  Click here to scroll (4 images attached)

Family

Badidae

Distribution

For many years this species was considered to have an enormous natural range covering parts of Pakistan, India, Nepal, Bangladesh, Bhutan, Myanmar and Thailand. Though widely distributed it is now known to be native to the Ganges River system with the Yamuna River in Himachal Pradesh state, India appearing to represent its northern limit. It is found in many other tributaries of the Ganges in India, Nepal and Bangladesh as far south as the river's estuary. Further south in India it inhabits the Mahanadi River system in Chhattisgarh and Orissa states and to the east parts of Assam state including the area around the city of Guwahati, the Kaziranga National Park and in the Dibru River. These latter localities lie close to the Brahmaputra River (the Dibru used to feed it prior to the 1950 Assam-Tibet earthquake). Historical records from western and southern India remain unconfirmed and it is likely that some of the data for the north of the country and Bangladesh actually refers toB. assamensis B. kanabos or B. chittagongis. It does not occur in Myanmar, Bhutan or Thailand and we've been unable to find any definitive records for Pakistan.

Though specific occurences are far too numerous to list here it is worth noting that the fish exhibit some variations in colouration and patterning depending on locality. Ideally the different forms should be labelled with the collection details by hobbyists and scientists alike in order to preserve bloodlines and maintain accuracy as some may turn out to be distinct species in the future. A 2004 phylogenetic study revealed that Badis from the Ganges/Brahmaputra and other Indian drainages were probably separated from the upper Ayeyarwady River populations between 19-23 million years ago.

Habitat

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 the Tumapao River, a tributary of the Ganges located 65km north of Calcutta. This is a wide (>100m), shallow (<1m depth), slow-moving stream that flows through rice fields and does not have a great deal of marginal vegetation. The water is described as "moderately turbid" and "brownish" with a substrate of mud in which some (unspecified) aquatic plants grow. Descriptions of other collection localities follow a similar theme; the fish appearing to favour turbid waters with low water flow and growths of submersed vegetation. It is often associated with waterlily beds and in the Dibru River occurs sympatrically with B. assamensis .

Maximum Standard Length

Around 2.4"/6cm for males, with females a little smaller.

Minimum Tank Size

A single pair can be housed in a tank measuring 24" x 12" x 12"/60cm x 30cm x 30cm/54 litres with a group requiring larger quarters.

Tank Setup

Badis badis will thrive in a heavily-planted set-up where the multitude of hiding places will provide it with the sense of security it needs to display natural behaviour. It will also appreciate the dimly-lit conditions towards the bottom of the tank where it will spend most of its time. A soft, sandy base is preferable although fine-grade gravel is acceptable and the substrate can even be omitted if you prefer, using plant species that can be grown attached to the decor such as MicrosorumTaxiphyllum or Anubias species. Driftwood branches, floating plants and leaf litter can all be added to lend a more natural feel while filtration and lighting need not be too strong. Some cave-like structures should be included to act as potential spawning sites; many breeders use half-coconut shells or upturned clay plant pots with drilled holes or parts of the rim removed to allow the fish access.

Temperature

This species is subject to seasonal temperature fluctuations in nature and is comfortable between 59 - 77°F/15 - 25°C with even greater extremes being tolerated for short periods. In many countries/well-insulated homes it can be therefore maintained without artificial heating year-round. Temperatures towards the upper end of this range are known to stimulate spawning activity meaning a heater will be required if you want to breed the fish outside of spring and summer months though. Set it to around 68 - 75°F/20 - 24°C for long-term care and breeding.

pH Range

Does best in slightly acidic to neutral water with a value of 6.0 - 7.5.

Hardness

3 - 15°H

Diet

Badis species are micropredators feeding on small aquatic crustaceans, worms, insect larvae and other zooplankton. They can be a little picky in the aquarium and may not accept dried foods although in some cases they will learn to take them over time. At any rate they should always be offered regular meals of small live or frozen fare such as ArtemiaDaphnia or bloodworm in order to develop ideal colour and conditioning. They are noted as somewhat shy, deliberate feeders (see 'compatibility').

Compatibility

Can be kept in a community tank provided tankmates are chosen with care. It is slow-moving with a retiring nature and may be intimidated or outcompeted for food by larger/more boisterous tankmates. Peaceful cyprinids such as Trigonostigma or smaller Rasbora species make good choices and we suspect it will also do ok with many South American characins, Otocinclus and similar small Loricariids or pygmy Corydoras catfish. Accommodating it in a biotope-style community of Indian fish is trickier although suitable species from the Ganges basin include Oreichthys cosuatis Pangio pangia and Colisa chuna . Certainly do not combine it with similar-looking, territorial bottom dwellers such as dwarf cichlids unless the tank is very large and never house it with other Badis species as hybridisation might occur. Also note that freshwater shrimp of the popular generaCaridina and Neocaridina, and certainly their young, may be preyed upon.

It is not a gregarious fish as such and rival males can be quite 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. The clever placement of caves can help enormously in this respect; do not be tempted to cluster all the available spawning sites in one area of the tank, for example.

Sexual Dimorphism

This species is very easy to sex but often only males are imported for the trade, presumably due to their brighter colours. Females are smaller, have duller patterning (they do not possess any blue colouration in the fins) and a noticeably shorter, rounder-looking body profile then males. Males also develop slightly extended finnage as they mature.

Breeding

Members of this genus are cave spawners that form temporary pair bonds and are not usually too difficult to breed provided the tank is arranged correctly (see 'tank set-up'). Other species 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 a cave to defend. Water parameters should be within the values suggested above. Feed the fish with plenty of live and frozen foods and spawning should not present too many problems.

As they come into breeding condition rival males will become increasingly combative and begin to display courtship behaviour towards females entering their chosen territory. During this process they display some wonderful changes in patterning with the body darkening to almost black and the blue fins intensifying in colour. The locking of mouths is also common; the male literally attempting to drag his partner into the cave. A receptive female will enter and spawning takes place with usually 30-100 eggs being laid.

Post-spawning the female is ejected and the male takes sole responsibility for the eggs and fry, defending the territory against intruders and fanning the brood with his fins. If you wish the other adult fish can be removed at this point although it is not absolutely necessary yet. The eggs usually hatch in 2-3 days but the fry do not become free swimming until they are 6-8 days old and may not leave the vicinity of the cave for another week or so after that. From then the adults (parent male included) may begin to regard them as food and are best transferred to a separate tank. The young fish are quite sedentary for the first few days meaning microworm is the ideal initial food but once they are visibly swimming in the water column Artemia nauplii can be introduced to the diet.

Notes

This species is sometimes sold under the trade name of 'chameleon fish' due to its ability to rapidly change colour, especially when breeding or stressed. It was originally described as Labrus badis by Hamilton but Bleeker reclassified it as Badis buchanani in 1854; he had adopted the species name 'badis' as the new name for the genus and wished to avoid using a tautonym. At that time the use of tautonyms was avoided in zoological taxonomy but is now permissible under ICZN rules meaning Badis badis is the correct combination.

Prior to 2002 the family Badidae included just five species of which only Badis badis and, to a lesser extent,Badis dario (referred to as B. bengalensis by some sources) were popular in the aquarium hobby. However an extensive revision paper by Kullander and Britz released that year resulted in the erection of no less than ten new species along with the genus Dario into which B. dario was moved and designated the type species. Dariocurrently contains only three members which are most easily distinguished from Badis by their small adult size (usually less than 1"/2.5cm), predominantly red colouration, extended first few dorsal rays/pectoral fins in males, straight-edged (vs. rounded) caudal fin, lack of visible lateral line and less involved parental behaviour. Badisspecies now number thirteen following the 2004 description of B. tuivaiei from the Manipur region of India, and the old subspecies of Badis badis such as B. b. burmicanus and B. b. assamensis have been elevated to full species level as B. ruber  and B. assamensis  respectively.

Some of them are not always easy to identify correctly. For example Badis badisB. chittagongisB. ferrarisiB. kanabosB. khwae B. ruber B. siamensis  and B. tuivaiei all exhibit a dark cleithral spot just above the base of the pectoral fin. However B. khwae B. ruber  and B. siamensis  all have an additional blotch on the caudal peduncle, and Badis badis can be told apart from B. kanabos by possessing a series of dark markings in the dorsal fin and/or at its base (vs. a single marking at the front of the fin) and only faint or indistinct vertical bars on the flanks (vs. a series of dark narrow bars). Badis badisB. chittagongisB. tuivaiei and B. ferrarisi only differ in some morphological counts although the latter has very distinctive patterning, displaying a series of black vertical bars along the centre of the flanks.

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; most notably for aquarists 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. In the 2002 revision paper all BadisDario and Nandusspecies were found to share a uniquely bifurcated (split) hemal spine on the penultimate vertebra and the authors hypothesise that this may represent evidence of the monophyly of this group. They further propose that the family Nandidae should be restricted to include only Nandus species with the other genera (PolycentrusMonocirrhusAfronandus and Polycentropsis) grouped together in Polycentridae. Following this system the Nandidae and Badidae are only separated by differences in morphology and egg structure although the phylogenetic relationships between them are yet to be fully-studied.

These recent studies have also shown that there exist five groups/clades within the genus, each containing species that are most closely-related to one another. The Badis badis group is distinguished only by the cleithral spot and contains Badis badisB. chittagongisB. ferrarisiB. kanabos and B. tuivaieiB. ruber B. siamensis and B. khwae  comprise the B. ruber  group and are most easily identified by the combination of cleithral spot plus caudal peduncle blotch. The B. assamensis  group consists of B. assamensis  and B. blosyrus  with a unique body pattern of light and dark striping while the B. corycaeus  group includes B. corycaeus  and B. pyema which possess an ocellated marking at the base of the caudal fin along with a reduction in the number of sensory pores on the head. The final group contains only B. kyar  which is separated by its relatively elongated body shape, pattern of vertical barring and band-like caudal fin marking. In the phylogenetic study this species was found to represent the sister group to either the B. ruber  or Badis badis/B. assamensis clades depending on the test performed and further studies are required to determine its exact placement within the genus. 

Literature cited

  1. Kullander, S.O. and R. Britz. 2002 - Ichthyol. Explor. Freshwat. 13(4):295-372.
    Revision of the family Badidae (Teleostei: Perciformes), with description of a new genus and ten new species.
  2. Rüber, L., R. Britz, S. O. Kullander and R. Zardoya. 2004 - Mol. Phylogen. and Evol. 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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