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.

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.

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…

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.

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…

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…

D. foerschi is sometimes traded as ‘boomerang barb’ or ‘Foersch’s fire barb’ and is included in a group of closely-related, similar-looking fishes which were moved into the new genus Desmopuntius by Kottelat (2013).

It can be told apart from other vertically-striped congeners by possession of additional dark blotches between the second, third and fourth vertical bars and a further marking at the posterior base o…

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 uncommon in the aquarium trade which is a little surprising given its huge natural range. Different populations can vary in colour pattern to an extent though all share the defining aspects given by Hamilton, comprising a diffuse yellow-golden marking on the operculum plus a dark spot on the caudal peduncle. The latter is usually surrounded by a variably-sized golden-yellow margin, and the dorsal-fin often contains irregular dark spots and streaks, these sometimes forming a longitudinal band.

This species is confused with P. ticto in much of the available literature and is sometimes listed as a synonym of it. Although some populations of the two species possess a similar colour pattern (there are reports of a P. ticto variant from the south of West Bengal state in India with a red, black-flecked dorsal-fin, for example) they do not occur in the same waters in nature and can be distinguished by examining the lateral line. This is complete in…