Sri Lanka

This species is euryhaline and mostly inhabits lowland, often coastal, habitats containing still or slow-moving brackish or freshwater. It displays a preference for habitats with surface vegetation or overhanging cover and is commonly found in mangrove swamps and rice paddies.

Aplocheilus spp. are surface-dwelling predators preying on both aquatic and terrestrial invertebrates. In the aquarium they will learn to accept dried foods in most cases but should also be offered regular meals of small live or frozen fare such as Artemia, Daphnia, chironomid larvae (bloodworm), etc.

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...

Butis spp. are largely nocturnal ambush predators with cryptic patterning to help them blend in with their surroundings. They can also lighten and darken their body colouration to an extent, have a habit of aligning themselves with solid surfaces whether horizontal, vertical, or inverted, and often swim in an upside-down position. The genus is usually included in the family Eleotridae of which members are often referred to...

Generally considered to have an enormous natural range extending from Iran to Taiwan and Bali, with records existing from Iran, Iraq, Afghanistan, Pakistan, Nepal, India, Sri Lanka, Bangladesh, Bhutan, China, Myanmar, Thailand, Laos, Cambodia, Vietnam, Malaysia, Indonesia, and Singapore. However there exists significant evidence to suggest that C. gachua as currently understood represents a complex of similar-looking species, and a taxonomic review of the group is clearly required.

Endemic to southwestern Sri Lanka where it appears restricted to the so-called ‘wet zone’ (see 'Habitat'). Confirmed localities are all within the Bentota and Kelani river systems and Kottawa Forest Reserve in Galle district, Southern Province. Type locality is given simply as 'Habitat in India orientale' and this appears to have caused confusion regarding the species' distribution with it of...

This species is diagnosable from other members of the genus primarily by its unique colour pattern which consists of 7-11 dark blue, irregularly-shaped, parallel vertical bars on the anterior portion of each flank plus a short horizontal stripe on the caudal peduncle which extends into the central caudal fin rays. Phylogenetic analyses suggest it's most closely-related to Indian Devario spp. plus D. xyrops from the western slope of the Rakhine Yoma mountains in Myanmar (Fang et al., 2009; Fang and Kullander, 2009).

Found in various types of habitat but shows a marked preference for shallow, slow-moving and standing waters such as rice paddies and other temporally-inundated environments with dense aquatic vegetation.

Wild examples are rarely-seen in the aquarium hobby although selectively-bred ornamental strains are widely-available for which care is identical. These are normally traded as 'red' or 'yellow' chromide and have a solid yellow-orange colour pattern with no dark elements. It exhibits a widespread sympatry with the con...

Endemic to Sri Lanka with type locality 'shaded pools of mountain streams at Akuressa, Southern Province, Sri Lanka, elevation 500 meters'. It's known from at least five localities, all of which are located in restricted to Sri Lanka's 'wet zone' in the southwest of the island, with records exis...

This species is available sporadically and makes an excellent choice for those new to keeping loaches. It's distinguishable from congeners by a combination of characters including: truncate/rounded caudal-fin; no scales on top of head; dark, squarish spots o...

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 continues to be mislabelled as O. melastigma, a name currently considered invalid by the majority of recent workers, or O. javanicus, a valid but distinct taxon. Roberts (1998) demonstrated that MClelland's description of Aplocheilus melastigmus, later renamed O. melastigma, does not correspond with any known Oryzias species from the Indian subcontinent or Myanmar since it's said to have a dark spot in the dorsal-fin and an excessively slim body, among other anomalies.

For many years this species was considered to occur in two colour forms with yellow or red dorsal, anal, and pelvic fins, respectively, but the red-finned variant has now been elevated to full species status as P. reval (Meegaskumbura et al. 2008). The latter is a smaller fish with a maximum SL of 33.6 mm recorded to date. As well as the obvious differences in body size and fin colour P. cumingii can be told apart from P. reval by the following...

Little sun is able to penetrate the forest floor so aquatic habitats are shaded and water temperature may be relatively cool, while conductivity and hardness are generally low and pH slightly acid. Macrophytes are uncommon though there may be dense, marginal vegetation, sometimes overhanging the full width of the stream, the roots of which may penetrate the banks underwater. Typical substrates are sandy but covered by a layer of leaf litter with fallen twigs and branches.

This species was considered a colour form of the related Pethia cumingii prior to its description. It can be told apart from P. cumingii by the following combination of characters: maximum standard length 33.6 mm (vs. 41.2 mm); smaller eye diameter (9.8-10.5, vs. 10.8-12.1 % SL); 11+13 (vs. 11+15) vertebrae; cleithrum with a single spine (vs. smooth); proximal arm of fifth ceratobranchial with an oval...

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.

Generally very peaceful making it an ideal resident of the well-researched community tank. As it places no special demands in terms of water chemistry it can be combined with many of the most popular fish in the hobby including other small cyprinids as well as tetras, livebearers, rainbowfishes, anabantoids, catfishes and loaches. It's a schooling species by nature, and at least 6-10 specimens should be purchased. Maintaining it in such...

P. chola was retained in Puntius sensu stricto, of which members are defined by the following combination of characters: adult size usually less than 120 mm SL; maxillary barbels absent or present; rostral barbels absent; 3-4 unbranched and 8 branched dorsal-fin rays; 3 unbranched and 5 branched anal-fin rays; last unbranched dorsal-fin ray weak or strong and unserrated; lateral line complete with 22-28 pored body scales...

As of 2006 only 4.6% of the old forest was left with the remainder existing only in small, highly-fragmented patches, most covering areas less than 10 km², of which some are now officially-protected reserves. Kottawa Forest is one of these and comprises just 15-20 hectares of wet, evergreen jungle, though the combined Kottawa-Kombala forest covers around 1600 ha. A number of minor, pristine streams...

It can be told apart from similar-looking congeners such as P. crescentus and P. muzaffarpurensis by the following combination of characters: barbels absent; lateral line incomplete with up to 5 pored scales; 20-22 lateral line scales; 8 predorsal scales; dorsal-fin with a vertically-orientated black streak and a black tip with orange markings; a dark spot at the base of the caudal peduncle.

These are still regarded as valid by some authorities although it's widely accepted that they represent variants of R. vaterifloris due to a lack of type material hindering conclusive study. Rasboroides nigromarginata (Meinken, 1956) has also been used to refer to a reddish form in which males differ from other populations in possessing dark fin margins, but the name is currently considered synonymous with R. vaterifloris by most sources despite the fish being rediscovered in 2010.

X. cancila is often seen referred to as 'freshwater garfish', and although it does superficially resemble the true gars of the family Lepisosteidae, it's actually a member of the Belonidae, or needlefishes, the majority of which are marine or estuarine in existence. There are currently just two species in the genus although the probable existence of a third member has been noted by Roberts (1989) among oth...

Wild swordtails are a fairly basic green colur. However the vast majority of swordtails available in the hobby today are hybrids of X.helleri with X.maculatus or X.variatus. There are a huge number of selectively-bred varieties available, including wagtail, lyretail, tuxedo, albino, neon, red, green and hi-fin. Swordtails may undergo what appears to be a change in sex. In young fish this may simply be late development. However some adult females develop male characteristics which is thought ...

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...

Type locality is the 'river below Calcutta' which corresponds to the western side of the Ganges River delta south of Kolkata, West Bengal state, with reports as to its wider distribution varying significantly. It's sometimes said to be present throughout India plus both mainland and maritime southeast Asia, but is more likely restricted to India, Bangladesh, Sri Lanka, and possibly Myanmar.

This species is also referred to as 'giant', 'great', 'cobra', or 'Indian' snakehead. Although currently-considered to be distributed throughout much of southern Asia it is widely-accepted to represent a complex of related species in need of additional research. A number of geographical variants exhibiting diffe...

Despite being a wholly unsuitable aquarium subject, C. idella is often traded as such, with an albino form having been developed specifically for the ornamental market. Individuals which have outgrown their aquarium or pond should never be released into natural waters, either, since this species has proven capable of causing serious environmental damage under a wide range of climatic conditions.

This species is euryhaline and mostly inhabits brackish estuaries, coastal lagoons and the lower reaches of rivers. It also occurs in freshwater habitats, however, including a number of inland lakes in Sri Lanka although it appears to have been introduced intentionally.

Prior to its description P. kamalika was referred to as P. amphibius, a putatively valid species probably restricted to western India. It differs from all congeners in the following combination of characters: 4½/1/2½ scales in a transverse line between the mid-dorsal...