Melawi

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.

G. filamentosa has appeared in the ornamental trade but is evidently delicate and therefore recommended only to experienced aquarists. It can be told apart from congeners by the following combination of characters: possession of filamentous dorsal and anal-fin rays in males; body transparent to translucent yellowish-brown colour in life; absence of a highly-extended second anal-fin spine; absence of carmine-red pigmentation in the dorsal, anal an...

The differences in pelvic-fin structure and gill openings led Roberts to redefine the genus when describing H. eubranchus, whereas Tan (2006) expressed doubts that the two are even congeneric but was unable to reach a definitive conclusion in the absence of fresh material. At any rate both species can be easily differentiated from Gastromyzon and Neogastromyzon spp. by observing the mo...

Given its wide natural range it seems logical that this species is or has been available in the aquarium trade, although its correct name may never have been applied. It is told apart from congeners by the following combination of characters: two pairs of barbels; a continuous midlateral stripe from the tip of the snout to the base of the caudal-fin, with a conspicuous small blotch at the posterior extremity, faintly marked on the caudal-fin; a faint mark between the anus and the anal-fin origin in juveniles; a narrow mouth.

In aquarium literature this species is also referred to as 'fine scaled tiger fish', 'Indonesian tiger fish', 'Sumatran tiger fish', 'Indo datnoid', and 'Indo dat'. The common name of 'tiger fish' is also used in reference to the African alestid genus Hydrocynus, and the more appropriate 'tiger perch' was suggested by Roberts and Kottelat (1994).

This species is distinguished from its Australian congeners S. jardinii and S. leichardti by possessing a lower number of lateral line scales (21-26 vs 32-36). It occurs naturally in a number of colour forms of which three were elevated to distinct species status in 2003, but the current majority view is that all represent S. formosus pending a detailed review. Kottelat (2013) mentions that the red form may...

This species is poorly known in general and is not present in the ornamental trade, although its name is widely misapplied to other Luciosoma species. Its congeners are mostly marketed as 'apollo shark', 'shark minnow', or similar, and often labelled with incorrect scientific names. Identification of the fish pictured here is based on Bleeker (1855, 1860) and Roberts (1989), plus drawings by Bleeker, thus...