Labyrinth Fishes

This species is readily available in the aquarium trade and is a good subject for those new to the hobby given its peaceable nature and relative adaptability in terms of water chemistry. It's sold under various names including A number of selectively-bred ornamental strains have also been produced including 'red', 'sunset', and 'golden', for which care is identical to the natural form.

Despite its ease of keeping and peaceable nature, this species is not particularly popular in the hobby, although it is imported quite regularly. A gold or 'sunset' strain exists, in which the barred patterning is replaced by an overall orange/gold colouration. This is not a natural variation, but has been selectively bred for the trade. The female of this form is almost as colourful as the male. Like others in the suborder Anabantoidei, the species possesses an accessory breathing...

It can be distinguished from congeners by its small adult size and presence of a single solid dark midlateral stripe on the body, above which is a series of dark blotches forming a second stripe. In the similar but larger, T. schalleri the upper stripe is more variable depending on the mood of the fish, sometimes fading entirely.

Known from the lower Mekong River basin in Laos, Thailand, Cambodia, and Vietnam, plus tributaries of the Chao Phraya watershed in central Thailand, and drainages between the Chao Phraya and Mekong in eastern Thailand. Type locality is 'Nam-Mun at Korat, 135 miles northeast of Bangkok, Thailand'.

The common name is derived from the ability of genus members to produce audible sounds via a specialised pectoral mechanism which is unique within the family Osphronemidae. The structure comprises modified pectoral-fin tendons and muscles which are stretched and plucked by basal elevations of two fin rays in a similar way to guitar strings via rapid beating of the fins. The pectoral-fins beat alternately, each able to generate short or long bursts of sound. These sounds are produced by both sexes, predom...

This species is a popular food fish in it's native countries. It is not often seen for sale these days, although it is both beautiful and peaceful. The alternative common name of 'Giant Gourami' is not particularly apt, although it is the largest species in the genus. Like others in the suborder Anabantoidei, the species possesses an accessory breathing organ known as the labyrinth organ. So-called due to its maze-like structure, this organ allows the fish to breathe atmospheri...

The Dwarf Gourami is one of the most ubiquitous freshwater species in the aquarium hobby, and is unarguably a beautiful fish. Several colour forms have been line-bred for the trade and have also proved popular. These include "Sunset" (also sold as "Red" or "Robin") and "Neon" varieties, although it's highly debatable whether these come close to matching the brilliance of the natural form. Unfortunately the general quality of dwarf gouramis availab...

Like others in the suborder Anabantoidei this species possesses an accessory breathing organ known as the labyrinth. So-called due to its maze-like structure this organ allows the fish to breathe atmospheric air to a certain extent. Comprising paired suprabranchial organs formed via expansion of the epibranchial (upper) section of the first gill arch and housed in a chamber above the gills, it contains...

An ideal species for the newcomer to 'oddballs'. It is exceptionally hardy, long-lived (it can survive for over 15 years when cared for properly) and exhibits some interesting behaviour. It appears to have evolved convergently with leaf fish of the genera Polycentrus and Monocirrhus (they're not closely related). All these species mimic leaves and other aquatic debris to assist them in hunting their prey. If you add live food to its tank, you will see the typical stalking behaviou...

This species is frequently mistaken for the similar-looking congener M. spechti Schreitmüller 1936, which is easily-identified by the absence of reddish pigmentation in the dorsal, anal, and caudal fins. There has been some debate as to whether these two represent the same taxon, however, with Winstanley and Clements (2008) proposing that M. erythropterus be considered a synonym of M. spechti because they were unable to separate the two species by morphological characters, and specimens with red pigmentation on the unpaired fins were coll...

In 1996 the species was known from five localities in Hong Kong, but at least one of these has been destroyed and it is now known only from Tai Po and Sai Kung districts. Additional populations have subsequently been discovered in Guangdong and Fujian provinces on the southern Chinese mainland. Type locality is 'China: Hong Kong: Tai Po: Sha Lo Tung'.

M. spechti is also sometimes referred to as M. concolor, particularly in older literature. A dispute regarding conservation of that name was resolved by the ICZN in 2006, however, since M. concolor Ahl, 1937 is a junior primary homonym of M. concolor Schreitmüller, 1936 and thus permanently invalid.

This species is also referred to as 'Kretser's paradisefish' and 'spotted gourami'. There exist three colour forms, two of which exhibit a greater degree of reddish or violet pigmentation in the fins, respectively. The third is more bluish and was described as M. kretseri minor by Deraniyagala (1958).

This species is sometimes traded under the names 'mini chocolate gourami', 'Burmese chocolate gourami' or mislabelled as the congener P. ocellatus, these two currently comprising the only known members of the genus. P. lineatus can be told apart from P. ocellatus via the following combination of characters: smaller body size (maximum standard length 18.7 mm vs. 32.0 mm); absence of ocellus-type marking in middle of each flank (vs. presence); presence of dark, stripe (vs. abs...

This species is most easily told apart from its only congener P. dayi by lacking (vs. possessing) two dark, irregular lateral stripes on the head and body, and a shorter caudal-fin in males. The results of phylogenetic analyses by Rüber et al. (2006) suggest that Pseudosphromenus is most closely-related to Malpulutta in an evolutionary sense.

Engmann (1909) mentions that the type series was collected from 'Malakka' but this is considered an error which probably should have read 'Kerala' since this species is known only from coastal drainages of the Western Ghats mountains in southern Kerala state, India.

A very hardy, beautiful species which is highly recommended to the beginner. A male in full breeding dress is one of the most stunning fish available in the hobby. T. leerii is alo fairly long-lived and may survive for 8 years or more in the aquarium. These fish will also consume the aquarium pest hydra....

T. microlepis is not as colourful as some other gouramis but can make a striking addition to the community tank. The modified ventral fins are considerably longer than in other gourami species. It is often used as a food fish in its native countries....

This species is not often seen for sale but is a very good addition to the larger community tank. It is cultured commercially for food in it's native countries, and is used to make a particularly tasty fish soup! The snakeskin gourami can also produce 'cracking' noises, especially during breeding or territorial exchanges....

This species is available in many different colour forms and varieties, all of which have been selectively bred for the aquarium trade. These are seen much more often than the natural form, which is the blue-grey three spotted fish. They include gold, opaline, cosby, marbled and silver forms. T. trichopterus is one of the hardiest fish commonly available in the trade and can adapt to many different water conditions. However it is recommended to the beginner with reservations regarding it's ...

This is the most colourful of the African anabantoids and is much sought after by hobbyists. A male in full breeding dress is truly a sight to behold. In nature it can be found in small streams, inhabiting areas of dense vegetation close to the riverbanks. It is difficult to collect a lot of fish from these habitats and so M. ansorgei is relatively rare in the hobby. These fish can be difficult to acclimatise but once settled are very hardy and can live up to 5 years in the aquarium....

This species is also referred to by the vernacular name 'Malay combtail'. In terms of external characters it differs most obviously from its only congener, B. signata by its overal brownish grey (vs. reddish) body colouration and presence of a mosaic-type patterning in the unpaired fins (vs. absence). The position of relatedness of the genus Belontia with respect to other anabantoids remains somewhat...

This species is also traded/referred to by the vernacular name 'Ceylon fighting fish'. It differs from its only congener, B. hasselti, by its overall reddish (vs. brownish-grey) body colouration, and absence (vs. presence) of a mosaic-like patterning in the unpaired fins. At least three putative phenotypes have been recorded. The nominative, and commonest, mostly inhabits clear streams in rainier zones...

Additonally, fin patterning in B. albimarginata, except the pectoral fins, consists of a broad white distal band, broad dark submarginal band with sharp outer margin and less sharp inner margin, and a plain red inner portion, while in B. channoides the dorsal fin is almost entirely red with only a thin white distal band and the dark submarginal band in the caudal fin does not extend into the uppermost portion of the fin. Base body colouration tends towards a brick-red shade in displaying male B. albimarginata, scarlet in B. channoides (pers. obv.).

The genus Betta is the most speciose within the family Osphronemidae with almost 70 recognised members and looks set to grow further with new ones continuing to be described on a regular basis since the turn of the century. Member species have successfully adapted to inhabit a variety of ecological niches from stagnant ditches to flowing hill streams including some extreme environments such as highly acidic peat swamp forests.

Likely to prey on insects and other small invertebrates/zooplankton in nature. Captive fish will normally accept dried products once they're recognised as edible, but should be offered plenty of small live or frozen foods such as Daphnia, Artemia or bloodworm regularly to ensure development of optimal colour and condition. Small insects such as crickets or Drosophila fru...

This species lends it name to the B. bellica group/complex of closely-related species within the genus, an assemblage of which members share the following set of characters: long and slender body with dorsal and ventral margins almost parallel; body depth 23-28 % SL; 30-33 anal-fin rays; 11-13 dorsal-fin rays; 32-34 total vertebrae; body dark brown in colour with iridescent green markings on each individual scale.

B. brownorum is included in the Betta coccina group/complex of closely-related species within the genus. This assemblage mostly comprises small, red-coloured fishes with the exceptions of B. persephone and B. miniopinna which are darkish. Identifying some of the red ones correctly is not always easy as the patterning in them can be both similar and confusingly variable. In B. brownorum and B. livida, for example, both male and female individuals may or may not possess a green lateral blotch.

B. burdigala is exceptionally rare in the hobby with many fishes traded or pictured as such being B. uberis or other congener. It's included in the Betta coccina group/complex of closely-related species within the genus. This assemblage mostly comprises small, red-coloured fishes with the exceptions of B. persephone and B. miniopinna which are darkish. Identifying some of the red ones correctly is not always easy as the patterning in them can be both similar and confusingly variable.

B. channoides and B. albimarginata together comprise the Betta albimarginata group/complex of closely-related species within the genus, these differing from all other members of the genus in colour pattern and by possession of 9-12 anal-fin spines (vs. 0-4). They look very similar to one another but differ in the following characters: anal fin spines 9-11 in B. albimarginata vs. 12 in B. channoides; anal fin rays 21-23 vs. 23-25; lateral scale rows 26-27 vs. 27.5-28; trans...

B. coccina can be told apart from other members by the following combination of characters: iridescent green lateral blotch present in male, absent in female; body dark red in colour; no parallel vertical iridescent gold opercle bars; pelvic fin falcate with black filamentous tip, remainder red; median fins with discrete iridescent green spots; dorsal fin-rays 9-12; anal-fin rays 27-29; subdorsal scales 7-8; lateral scales 31-32; predorsal scales 18-21. The genus Betta is the most speciose within the family Osphronemidae with almost 70 reco...

The type locality is a stream in a forest swamp with dense growth of Barclaya motleyi at intervals, part of which had been turned over to cultivation of rubber trees in 1997. The water depth varied between 5-80 cm, pH was 5.8 and syntopic species included 'Puntius' banksi, Rasbora einthoveni, Trigonopoma pauciperforatum, Hemirhamphodon pogonognathus, Betta pugnax, Sphaerichthys osphromenoides, Trichogaster trichopterus, Channa gachua and C. lucius.

This species is available in the aquarium hobby but is not traded in large numbers and may have been inadvertently hybridised with the similar-looking congener B. rubra prior to its description since they're typically exported mixed together. It's included in the B. rubra group of closely-related species within the genus, an assemblage erected by Schindler and van der Voort (2012) who...

This species is often confused with B. krataios in the aquarium trade, the latter having been known as B. sp. 'Kapuas' prior to description. The two can easily be told apart as the caudal-fin is rounded in B. krataios but spade-shaped and in adults, highly-extended in B. dimidiata. Together these two comprise the B. dimidiata group of closely-related species within the gen...

This species is the only member of the B. edithae group within the genus, and separated from all other Betta spp. by the fact that the branchiostegal membrane and posterior portion of the opercle are opaque or translucent. The original diagnosis by Vierke also states that it has relatively small eyes and short fins with a typical pattern of partial barring.

This species is included in the B. pugnax complex of closely-related species within the genus, an assemblage of which members are notoriously difficult to tell apart from one another, but which can be characterised collectively by the following set of shared characters: relatively large head measuring 28-40% SL; live colouration usually brown with green or blue iridescent spots; male with similarly-coloured scales on opercle, sometimes extending to abdomen; juveniles and females usually brown with two central body stripes and a dark marking on the caudal peduncle; anal-fin in mature specimens pointed and often elongated; caudal-fin lanceolate.

B. falx is included in the Betta picta group/complex of closely-related species within the genus, an assemblage comprising species with the following shared characters: unpaired fins rounded (anal-fin sometimes tapering to a blunt point); anal-fin rays I-III, 18-24; dark marginal band on anal and caudal fins, more pronounced in mature males; presence of pre-orbital and post-orbital stripes; presence of chin bar on throat; iridescent green, gold, or blue scales on opercle.

This species lends its name to the Betta foerschi group of closely-related species within the genus, of which members share the following set of characters: possession of iridescent blue or green unpaired fins; rays and interradial membranes in unpaired fins not contrasting; dorsal fin with thin, bright white distal band; opercle with two, reddish-yellow, vertical bars. Members are regarded as being closely-related to bubble nesting Betta specie...

Presumed endemic to the geographically-isolated Maliau basin, a roughly circular plateau enclosed by hills in Sabah state, Malaysia, Borneo. The Maliau River is part of the much larger Kinabantangan watershed, Malaysia's second longest river. The type series was collected from heath forest alongside 'Puntius' sealei and Hemibagrus cf. baramensis in acidic water with a pH of 4.2-4.8. Adult individuals were spaced around a metre apa...

This appears to be an undescribed species, and has only been available to the aquarium hobby in limited numbers to date. The rather long-winded trade name derives from the fact that it was initially marketed as two different species, i.e., B. sp. 'Sengalang' and B. sp. 'Palangka'. The spelling of the latter was later corrected but the fish may still be seen with either or both names attached. It looks very similar to fis...

The easiest way to distinguish these is by examining the throat markings, which vary according to species, and in the case of B. hipposideros form a black horse-shoe shape. It can also be separated from other group members by the following suite of characters: dark blotch on throat joined to black lower lip; presence of transverse bars in dorsal and caudal fins; absence of dark margin in anal-fin; opercle usually with gold scales, without iridescrent green scales; ventral margin of opercle brown; 6.5-7 subdorsal scales (mode 6.5); 9-10 postdorsal scales (mode 9.5); 31-32 lateral scales (mode 32).

B. ibanorum is uncommon in the hobby and is apparently more frequently fished for food than the aquarium trade. It's included in the Betta akarensis group/complex of closely-related species within the genus, of which members share the following set of characters: possession of pre-orbital and post-orbital stripes (the post-orbital stripe is faint or interrupted in some species); chin bar present; caudal-fin lance...

Prior to official description this species was traded as B. sp. 'Laut'. It's included in the Betta unimaculata complex of closely-related species within the genus, , of which members share the following set of characters: body long and slender with depth at dorsal fin origin 18-25 % SL; head large and blunt with width 19-24 % SL; long maxilla and lower lip with distance from tip of lower jaw to posterior end of maxilla 27-54 % HL; caudal-fin rounded in sha...

B. imbellis is included in the Betta splendens complex of closely-related species within the genus, of which members share the following set of characters: head length short 22-31 % SL; often a brightly-coloured body; iris of the eye with iridescent green or blue patches; body elongate or slender; opercles parallel when head viewed dorsally; caudal-fin rays red or brown and contrasting with the iridescent interradial membranes; unpaired fins without an irides...

This species was traded as B. sp. 'Kapuas' prior to its formal description and continues to be mislabelled B. dimidiata. The two can easily be told apart as the caudal-fin is rounded in B. krataios but spade-shaped and in adults, highly-extended in B. dimidiata. Together these two comprise the B. dimidiata group/complex of closely-related species within the genus, members of which can be characterised b...

It can be told apart from other members of the B. pugnax group by the following characters: caudal fin rounded in both males and females; chin bar and second postorbital stripe absent; adult males possess intensive blue or bluish-green iridescent (blackish in preservation) colouration on the sides of the head and throat extending from the snout tip to posterior edge of opercle; possession of two central body stripes, the upper extending from the pec...

It can be told apart from other members of the B. pugnax group by the following characters: chin bar absent; prsence of transverse bars in the dorsal-fin; no transverse bars in caudal-fin; green iridescent scales present on opercle and body; anal fin with iridescent, light blue distal band; a pair black markings below the postorbital stripe on the opercle of females and juveniles; anal-fin rays 25-29 (mode 28); lateral scales 28-30 (mode 29); postdorsal scales 10-11 (mode 12); pelvic-fin length 34.8-50.6% SL; head length 33.4-36.8% SL; inter-orbital width 31.7-37.4% HL.

This species is included in the B. coccina group/complex of closely-related species within the genus. This assemblage mostly comprises small, red-coloured fishes, with the exceptions of B. persephone and B. miniopinna which are darkish, and identifying some of them can be problematic as the patterning in them can be both similar and confusingly variable. Members possess the foll...

B. macrostoma is included in the Betta unimaculata complex of closely-related species within the genus, of which members share the following set of characters: body long and slender with depth at dorsal fin origin 18-25 % SL; head large and blunt with width 19-24 % SL; long maxilla and lower lip with distance from tip of lower jaw to posterior end of maxilla 27-54 % HL; caudal-fin rounded in shape, occasionally with elongated median rays; pelvic-fin short and filamentous; dorsal and anal fins relatively pointed.

Known only from a handful of localities in Bangkok, Samut Sakhon, Samut Songkhram and Samut Prakan provinces in central Thailand, all of which lie on the coast of the Gulf of Thailand. Most habitats are in close proximity to Bangkok, which continues to expand rapidly, are considered under extreme threat, and recent surveys have failed to confirm that the fish is still present in Samut Songkhram and Samut Prakan.

This species was known as B. sp. 'Mandor' or B. sp. 'ninja' prior to official description. It belongs to the Betta foerschi group/complex of closely-related species within the genus, of which members share the following set of characters: possession of iridescent blue or green unpaired fins; rays and interradial membranes in unpaired fins not contrasting; dorsal fin with thin, bright white distal band; opercle with two, reddish-yellow, vertical bars. Members are regarded as being closely-related to bubble-nesting Betta species since they share exhibit certain similarities in morp...

Not recommended for the standard community set-up for reasons already touched upon. It's requirements and disposition mean it's best kept alone or with very peaceful species since much bigger or more vigorous fishes are likely to intimidate and outcompete it. Some small cyprinids and loaches that inhabit similar environments in nature are compat...

Bintan has been developed for tourism over the last decades and is heavily-promoted by Indonesia, with luxury beach resorts and golf courses increasing in number. Further deforestation has occurred in order to establish large rubber plantations in the interior of the island. B. miniopinna is now restricted to a few remaining pockets of primary peat swamp forest and has been listed as 'Critically Endangered' on the IUCN Red List of Threatened Species since 1996.

This species is included in the Betta unimaculata complex of closely-related species within the genus, of which members share the following set of characters: body long and slender with depth at dorsal fin origin 18-25 % SL; head large and blunt with width 19-24 % SL; long maxilla and lower lip with distance from tip of lower jaw to posterior end of maxilla 27-54 % HL; caudal-fin rounded in shape, occasionally with elongated median rays; pelvic-fin short and filamentous; dorsal and anal fins relatively pointed.

Has been collected from a slowly-moving creek which ranged in depth from 20-50 cm. The water was clear and slightly-stained with tannins and the subtrate was covered by a layer of leaf litter. PH was 6.3, conductivity 82 µS/cm and water temperature 25.5°C. At another locality pH was 6.5, conductivity 69 µS/cm and water temperature 26.6 °C.

This species is included in the Betta waseri group/complex of closely-related species within the genus, an assemblage which also includes a handful of unidentified fishes such as B. sp. 'Medas' on an unofficial basis. Group members share the following combination of characters: base body colouration clay yellow; opercle scales iridescent gold in mature males of all species except ...

This species is included in the Betta unimaculata complex of closely-related species within the genus, of which members share the following set of characters: body long and slender with depth at dorsal fin origin 18-25 % SL; head large and blunt with width 19-24 % SL; long maxilla and lower lip with distance from tip of lower jaw to poste...

B. persephone can be told apart from other members of the group by the following characters: no lateral blotch; body blackish; dorsal surface of head posterior to eye sloping gently; no parallel vertical iridescent gold opercle bars; pelvic-fin falcate with white filamentous tip, remainder black to reddish; median fins covered diffusely with light green iridescence; dorsal fin-rays 9; anal-fin rays 24-27; subdorsal scales 6-7; lateral scales 27-29; predorsal scales 17-18.

B. pi is included in the Betta waseri group of closely-related species within the genus, an assemblage within which members share the following combination of characters: base body colouration clay yellow; opercle scales iridescent gold in mature males of all species except B. tomi; throat with black markings which join with black lower jaw in some species; no chin bar.

This species lends its name to the Betta picta complex of closely-related species, an assemblage of which members share the following combination of characters: unpaired fins rounded (anal fin sometimes pointed): I-III, 18-24 anal-fin rays; anal and caudal fins with dark distal margins, most pronounced in mature males; pre- and post-orbital stripes present; chin bar present; opercle with iridescent blue, green, or gold scales.

B. pinguis is included in the Betta akarensis group/complex of closely-related species within the genus, of which members share the following set of characters: possession of pre-orbital and post-orbital stripes (the post-orbital stripe is faint or interrupted in some species); chin bar present; caudal-fin lanceolate with highly extended median rays in mature males; caudal fin usually with transverse bars; greenish or bluish iridescent scales on body of males in some species; opercle without iridescent scales except in juveniles.

It can be told apart from other members of the B. pugnax group by the following characters: second postorbital stripe on opercle complete; no transverse bars in caudal-fin; 20-22 predorsal scales; preanal length 50.6-54.8 % SL. Not all authors consider it a member of this group, however, with some placing it in the B. picta complex, e.g., Schindler and Schmidt (2006). The genus is th...

It can be told apart from other members of the B. pugnax group by the following characters: chin bar present; no complete second postorbital stripe on opercle; presence of transverse bars in caudal-fin of males; caudal-fin in males broadly lanceolate; opercle scales iridescent blue; anal-fin with reddish subdistal band and black margin; caudal-fin without dark margin; 25-28 anal-fin rays; 28-31 lateral scales; 11-12 postdorsal scales; length of pelvic fins 26.6-43.8 % SL; length of head 27.5-35.2 % SL; inter-orbital width 32.4-53.0 % HL.

Restricted to remnant blackwater habits in heavily-disturbed areas of former peat swamp forest, the original vegetation having been cleared to make space for plantations of oil pal, pineapple and rubber. It's now typically found among overhanging marginal vegetation of irrigation canals, with sympatric species including Belontia hasseltii, Betta bellica, B. imbellis, Sphaerichthys osphromenoides, Parosphromenus sp., and Trichopsis vittata. PH in its natural waters has been recorded over the range 3.9 - 4.2.

It should be noted that not all authors consider the B. pugnax group to contain the same species, with some placed in the B. picta complex by Schindler and Schmidt (2006), for example. B. raja can be told apart from other members of the B. pugnax group by the following characters: mature males with very long pelvic fins covering 15-23 anal-fin rays or even longer than the base of the anal-fin in some cases; anal-fin and lower caudal-fin with black marginal bands; 25-28 anal-fin rays; 30-32 lat...

This species was previously included in the Betta foerschi group of closely-related species within the genus, but following its redescription in 2012 now lends its name to the B. rubra group. It was first placed into its own species group by Witte and Schmidt (1992), primarily on the basis of a triangular marking that appears below the eyes of the fish, although Tan and Ng (2005) suggested that this feature is insufficient to warrant the fo...

This species is included in the B. coccina group/complex of closely-related Betta species within the genus. This assemblage mostly comprises small, red-coloured fishes, with the exceptions of B. persephone and B. miniopinna which are darkish, and identifying some of them can be problematic as external patterning can be both similar and confusingly variable.

This species was considered a colour form of the closely-related B. imbellis and commonly-referred to as 'black imbellis' prior to description due to its blackish opercle and body. It's also previously been confused with B. splendens due to the colour of the vertical opercular bars which tend to be reddish (but may also be pale red, greenish-silvery, plain silvery or without colour in some populations), but DNA analysis has demonstrated it...

This species is included in the B. bellica group/complex of closely-related species within the genus, an assemblage of which members share the following set of characters: long and slender body with dorsal and ventral margins almost parallel; body depth 23-28 % SL; 30-33 anal-fin rays; 11-13 dorsal-fin rays; 32-34 total vertebrae; body dark brown in colour with iridescent green markings on each individual scale.

B. simplex is included in the Betta picta group/complex of closely-related species within the genus, an assemblage comprising species with the following shared characters: unpaired fins rounded (anal-fin sometimes tapering to a blunt point); anal-fin rays I-III, 18-24; dark marginal band on anal and caudal fins, more pronounced in mature males; presence of pre-orbital and post-orbital stripes; presence of chin bar on throat; iridescent green, gold, or blue scales on opercle.

This species is included in the Betta splendens complex of closely-related species within the genus, of which members share the following set of characters: head length short 22-31 % SL; often a brightly-coloured body; iris of the eye with iridescent green or blue patches; body elongate or slender; opercles parallel when head viewed dorsally; caudal-fin rays red or brown and contrasting with the iridescent interradial membranes; unpaired fins without an iridescent margin; opercle with red or blue vertical bars in males; dorsal-fin rays 0-II, 7-9; anal-fin rays II-V, 21-26.

This hypothetically-undescribed species appears to be a member of the Betta unimaculata complex of closely-related species within the genus, of which members share the following set of characters: body long and slender with depth at dorsal fin origin 18-25 % SL; head large and blunt with width 19-24 % SL; long maxilla and lower lip with distance from tip of lower jaw to posterior end of maxilla 27-54 % HL; caudal-fin rounded in shape, occasionally with elongated median rays; pelvic-fin short and filamentous; dorsal and anal fins relatively pointed.

Inhabits freshwater swamps and associated streams, typically shaded from the sun by dense riparian vegetation. The water is normally clear or lightly stained with tannins, and the fish found in water less than a metre deep alongside related species including Betta edithae, B. miniopinna, and B. fusca. PH has been measured to range between 4.9-5.5.

This species' common name is derived from the tradition of keeping the fish in order to fight against each other in organised 'bouts' upon which participants and onlookers place wagers. It has been extensively line-bred for vigour, strength, and the ornamental trade, and hybridised with the congeners B. imbellis, B. smaragdina, and B. mahachaiensis.

Known only forest hill streams with flowing, clear water. These are typically shaded from the sun by dense riparian vegetation. The substrate is composed of rocks or gravel, fallen leaves, branches and submerged tree roots, and presumably the fish show a preference for quieter marginal zones as with related congeners. The type locality was described as a 'swampy stream' and sympatric species incl...

At one locality close to Serian, Sarawak, the habitat comprised a swiftly-flowing, clear hill stream with a substrate of quartz gravel and variably-sized rocks. The pH was 7.0 and there was no aquatic vegetation. The stream was approximately 10 metres across at its widest point and between 5-80 cm deep. B. taeniata was found in sluggish stretches among submerged tree roots, leaf litter, or overhanging riparian vegetation.

This poorly-known betta is included in the B. coccina group of closely-related species within the genus. This assemblage mostly comprises small, red-coloured fishes, with the exceptions of B. persephone and B. miniopinna which are darkish, and identifying some of them can be problematic as external patt...

The majority of records pertain to an area sandwiched between the lower Arut and Kumai rivers, south of the towns of Pangkalan Bun and Kumai in Kalimantan Tengah (Central Kalimantan) province, Borneo, Indonesia. Addditional collections have taken place in the Sampit river basin to the east, and several hundred kilometres further north in Sukadana district Kalimantan Barat (West Kalimantan) province. Type locality is 'Indonesia: Borneo: Kalimantan Tengah: Arut basin: Pankalanbun', with the specimens having been obtained from the aquarium trade.

This species is included in the Betta unimaculata complex of closely-related species within the genus, of which members share the following set of characters: body long and slender with depth at dorsal fin origin 18-25 % SL; head large and blunt with width 19-24 % SL; long maxilla and lower lip with distance from tip of lower jaw to posterior end of maxilla 27-54 % HL; caudal-fin rounded in shape, occasionally with elongated median rays; pelvic-fin short and filamentous; dorsal and anal fins relatively pointed.

One of the smallest species in the genus, it is rarely seen in the trade. A pity, as its diminutive size makes for an ideal aquarium subject. Like others in the suborder Anabantoidei, the species possesses an accessory breathing organ known as the labyrinth organ. So-called due to its maze-like structure, this organ allows the fish to breathe atmospheric air to a certain extent. It is formed by a modification of the first gill arch, and consists of many highly vascularised, folded flaps of sk...

This species is also referred to by the alternative vernacular name of 'noble gourami' and is currently the only recognised member of the genus Ctenops. It is usually regarded as being very difficult to keep whereas in reality it is quite adaptable once acclimatised but appears to react poorly to the export and shipping process meaning it is often seen on sale in poor condition and susceptible to or already infested with secondary health issues such as Oödinium, to which it appear...

The pinkish-white form of this species is among the most widely-traded aquarium fishes in the world but does not occur naturally and is in fact a leucistic variant bred specifically for ornamental purposes. The 'short-bodied' or 'balloon' variety also continues to be fashionable but under no circumstances do we recommend the purchase of these intentionally disfigured animals which tend to have much shorter life spans than the naturally-shaped fish. There also exists a less-po...

M. ocellatus can be distinguished from congeners by the following combination of characters: caudal-fin rounded; eye stripe not connecting spot on posterior projection of opercle with eye; dorsal-fin rays filamentous posterior to a vertical through the posterior anal-fin rays in adults; 16-19 spinous dorsal-fin rays; 6-13 rakers on ceratobranchial of first gill arch; posterior tip or margin of body scales not darker than scales.

M. opercularis is a classic aquarium fish, having been introduced to the hobby by a French soldier named Gerault in 1869. Of the initial 100 specimens shipped, 22 survived and were successfully bred later that same year by another Frenchman, the Parisian Pierre Carbonnier. This gives the species the distinction of being one of the very first ornamental fish imported to Europe. It is also known as 'Chinese fighting fish', 'paradise gourami', and 'blue paradise fish'.

M. fasciolatum is found in clear water with lots of surface and overhanging vegetation in nature.

A bizarre and very recent addition to the genus, O. exodon is infrequently imported to the hobby, but has been seen occasionally. It has specially adapted mouthparts whereby it has greatly enlarged teeth. An extra set of teeth can also be seen growing in concentric bands on the outer lips! These are used in nature to literally 'pick' fruit from overhanging branches, with the fish often leaping from the water to grab a particularly juicy fig or other fruit. When the mouth of the fish is...

An incredibly hardy, long-lived fish which can survive for over 20 years in captivity. These fish develop real personality and can learn to recognise their owner. They are often sold as cute juveniles in aquatic shops with no information provided as to their adult size. The young have an attractive barred patterning which fades as the fish grow, which they do very quickly. A golden variety also exists in aquaria. O. goramy is cultured commercially for food on a large scale in several countrie...

Still relatively rare in the hobby, this fish was only described to science in the early 1990s. It's not yet being mass-produced in any great numbers, and demand is high, so it's quite pricey when it is available. It's a stunning fish when adult, developing bright red fin edges with filamentous extensions, and a body colour varying between blue-green and almost black. It makes a great pet as it can develop real personality and learn to recognise its owner....

To date the species is known mostly from the upper Ayeyarwady River basin in northern Myanmar where it's been collected close to the city of Myitkyina in Kachin State as well as around nearby Lake Indawgyi, the largest inland lake in Southeast Asia and home to ten globally threatened bird species. The lake and surrounding area were designated a protected zone by the Ministry of Ecotourism in 1999 and now form the Indawgyi Lake Wildlife Sanc...

Type locality is 'Kota Tinggi, Mawai-Desaru road, Johor, Peninsula Malaysia' and this species is endemic to a small portion of eastern Johor state, Peninsular Malaysia around the towns of Kota Tinggi, Mawai and Desaru. A great deal of its original habitat has been lost via deforestation and other human alterations and it's considered in grave danger of extinction.

Type locality is given only as 'Sarawak state, Borneo, East Malaysia', with the material deriving from Sibu Division in western Sarawak. It's since been recorded at other localities within Sarawak, to which it appears endemic, but it remains unclear whether all represent a single species or not with those from the area around Lundu in northwestern Kuching Division in par...

It's care requirements, disposition, and especially conservation status dictate that it should be maintained alone or alongside a group of small, peaceful cyprinids such as Boraras or Sundadanio spp. Likewise, different Parosphromenus spp. should not be kept together since the females of many are very difficult to tell apart and some are undoubtedly capable of hybridising.

This species is not generally available in the aquarium hobby on a commercial basis but is occasionally collected and distributed by private aquarists. It's name is sometimes misapplied to commercial shipments of other species, and there also exist a number of other fish with rounded caudal-fins that may or may not be conspecific, including P. sp. 'blue line' and P. sp. 'Selatan' from Sumatra.

P. deissneri was the only recognised member of the genus for almost a century following its description in 1859. As a result its name has and continues to be widely misapplied in both aquarium and ichthyological literature although it's probably always been very rare in the hobby, while a number of fishes previously identified under the name from other pa...

Parosphromenus spp. have been grouped arbitrarily based on courtship behaviour in males which adopt a 'head-down', 'head-up', or 'horizontal' position depending on species. P. harveyi belongs to the former, most abundant, assemblage in which the male assumes a near-vertical position with the head lowermost and fins splayed during nuptial displays.

This species is said to be slightly easier to maintain than the majority of congeners and is therefore a recommended choice for those new to maintaining Parosphromenus spp. in the aquarium. It's occasionally available on a commercial basis and we've seen it traded as 'moonspot licorice gourami' in the past. There exist at least three colour forms on...

In males the dorsal, anal and caudal have a black subdistal band bordered on either side by bluish iridescent bands, with the inner one significantly thicker. The pelvic fins are iridescent emerald green with a dark blotch at the base and a subdistal dark spot, while the pectoral fins are hyaline.

Endemic to Central Kalimantan (Kalimantan Tengah) province, Borneo, Indonesia although the full extent of its range remains somewhat unclear. Initial collections were from the southwestern tip of the province, in the Jelai Bila river basin near Sukamara and Lamand basin close to Pangkalan Bun, both of which are tributaries within the Arut drainage, while it's subsequently been recorded in the Benipah river system further east.

This species has occasionally appears in the aquarium trade in substantial quantities but is not an easy species to maintain in captivity and often susceptible to disease post-import. It's sometimes sold as 'ornate licorice gourami'. It's among the smallest members of the gen...

This species has occasionally been traded on a commercial basis and was known as P. sp. 'Manis Mata' prior to description, with the latter apparently referring to a location some 100 km away from the type locality where the fish do not occur. It's said to be slightly easier to maintain than the majority of congeners and is therefore a recommended choice for those ne...

This fish has been widely available in the aquarium trade in recent years and is sometime referred to by the invented name P. 'sintangensis'. It displays a close resemblance to P. bintan and another unidentified fish known to aquarists as P. sp. 'blue line' although the inner bluish bands in the dorsal, anal and caudal fins are perhaps a little narrower in P. sp. 'Sentang' than the other two.

This species has been known in the aquarium hobby since the mid-twentieth century but has almost always been identified as the congener P. deissneri and appears as such in the majority of aquarium literature. It can be told apart from congeners by the colour pattern in adult males (see 'Sexual Dimorphism') plus possession of 11-12 spinous dorsal-fin rays, 13-14 spinous anal-fin rays and 6-8 segmented anal-fin rays.

There are only two described species in the genus Sandelia. Both have limited natural ranges in parts of South Africa, which in itself is odd as they're completely isolated from other genera of anabantoids. This is probably due to some ancient radiation of species, but as yet remains unresolved. Sandelia spp. are also considered the most primitive of anabantids, as they possess a less well-developed labyrinth organ than their relatives. S. capensis is of considerable conservation importa...

This species is traded under several names of which others include 'sharp-nosed gourami', 'moonlight chocolate gourami', 'black-lined chocolate gourami' and 'black-tailed chocolate gourami', though it's far from common in the hobby. Its unique colour pattern makes it difficult to confuse with any of the three other members of the genus even in the absence of meristic data.

The genus Sphaerichthys currently comprises four species with S. osphromenoides by far the best known in the hobby. It's easily distinguishable from the congeners S. vaillanti and S. acrostoma since both exhibit a notably more elongate head and body profile, reverse sexual dimorphism (i.e. females are the more colourful/strongly-patterened), and are paternal mouthbrooders.

This species is only occasionally seen in the hobby and sometimes sold as 'cherry chocolate gourami'. It was originally described as a subspecies of S. osphromenoides since the two are very similar-looking but has been considered a species in its own right since the late 1980s. The two differ in the number ofrays (7 in S. selatanensis vs. 9-10 in S. osphromenoides),rays (7 vs. 8),...

This species is traded under several names of which others include 'Samurai gourami' and 'Samurai Zebra Chocolate Gourami'. Though the former of these is arguably the most common, these names are potentially misleading since the fish is neither especially combative nor from Japan. Its unique colour pattern makes it difficult to confuse with any of the three other members of the genus even in the abse...

This species isn't especially popular in the aquarium trade but is undoubtedly interesting despite its lack of colour. In addition to its survival ability in the absence of water it's also capable of producing audible sounds though the purpose of these has not been fully-studied. Naturally-occurring xanthic and albino forms have also been recorded. There is considerable confusion as to the taxonomic status of the two species currently occupying this genus, with ichthyologists widely...

B. chloropharynx is included in the Betta waseri group/complex of closely-related species within the genus, an assemblage which also includes a handful of potentially new species such as B. sp. 'Medas' on an unofficial basis. The easiest way to distinguish these is by examining the throat markings which vary according to species. In this case the lighter of these form a shape that roughly resembles a horizontal figure of ei...

This species is included in the Betta unimaculata complex of closely-related species within the genus, of which members share the following set of characters: body long and slender with depth at dorsal fin origin 18-25 % SL; head large and blunt with width 19-24 % SL; long maxilla and lower lip with distance from tip of lower jaw to posterior end of maxilla 27-54 % HL; caudal-fin rounded in shape, occasionally with elongated median rays; pelvic-fin short and filamentous; dorsal and anal fins relatively pointed.

This species can be exceptionally long-lived and there are reports of specimens surviving in aquaria for over 30 years. It is named after the explorer Mary Kingsley, and often goes by the common name of Kingsley's climbing perch. While Ctenopoma are closely related to the Asian climbing perch (Anabas sp.), they are not known to have the ability to cross areas of land like this species. Like others in the suborder Anabantoidei, the species possesses an accessory breathing organ known as t...

There are currently 20 species of Ctenopoma, most of which most are seldom seen in the aquatic trade. Originally the genus was significantly larger, but a number of original members were reclassified by Norris in 1995. Whilst describing what were apparently two new Ctenopoma, he discovered sufficient morphological anomalies in the fish to erect a new genus for them. The name Microctenopoma was chosen, although this does not relate to the size of the fish. Similar defining characteristics were al...

With a reputation as a difficult species to maintain in captivity, L. pulcher is recommended only to those enthusiasts able to provide the specialist diet and care it requires for its long-term health. It seems to travel very poorly, and is often seen on sale in a weakened, emaciated state. It is also particularly susceptible to bacterial infections when initially imported. Observe the fish carefully when buying and avoid any that are showing red patches around the mouthparts or fins, or that ap...

This species is included in the Betta waseri group/complex of closely-related species within the genus, an assemblage which also includes a handful of potentially new species such as B. sp. 'Medas' on an unofficial basis. Group members share the following combination of characters: base body colouration clay yellow; opercle scales iridescent gold in mature males of all species except B. tomi; throat with black markings which join with black lower jaw in some species; no chin bar.

There are only two described species in the genus Sandelia. Both have very limited natural ranges in parts of South Africa, which in itself is odd as they're completely isolated from other genera of anabantoids. This is probably due to some ancient radiation of species, but as yet remains unresolved. Sandelia spp. are also considered the most primitive of anabantoids, as they possess a less well-developed labyrinth organ than their relatives. You're unlikely to see any of these fo...