It can be distinguished from congeners by the following combination of characters: 61-68 scales in the lateral series; a small, well-defined, sometimes ocellated black spot on the shoulder and another in the centre of the caudal peduncle; body without longitudinal stripes formed by spots on scales; caudal fin uniformly dusky or colourless, lobes without stripes or black margins.

While separating some of the fish that may be found on sale as ‘C. siamensis’ is a tricky task, C. nigriloba is quite simple to identify. The dark lateral body stripe uniquely breaks up into a series of blotches when the fish are sparring, stressed or sleeping and the lower caudal fin lobe contains dark pigmentation suffused with red. The latter feature has given rise to the trade name of ‘penguin flying fox’.

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…

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.

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…

D. johorensis can be distinguished by the following combination of characters: 5-6 dark, lateral stripes on body in specimens larger than 40 mm; stripes immediately above and below the central stripe (stripes ‘+1’ and ‘-1’, respectively) located on scale rows +2 and -2, not touching dorsal and ventral midlines (except in some small specimens from Peninsular Malaysia); stripes broad, typically between 0.5-1 scale rows deep…

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…

This species appears is rare in the aquarium hobby with the majority of images both online and in the published literature instead depicting H. confuzona or H. parclitella. All three are members of the H. ocellata ‘group’ within the genus which currently contains H. ocellata, H. bilineata, H. confuzona, H. orthogoniata, H. ogilviei and H. parclitella.

Following Tan and Ng (2005) these share possession of…

This is the most commonly-encountered representative of the genus in the aquatic trade though is by no means common. As in other members of the genus body colouration is highly variable, even among individuals collected from a single locality, although a few useful regularities have been observed which can be used to distinguish certain species. This is thought related to the fact that Acrochordonichthys spp. periodically shed their skins and appear paler post-moulting.

A. rugosus lends its …

This is one of two species traded under the vernacular name ‘tinfoil barb’, the other being the less well-known congener B. altus. Despite this it appears that B. altus is just as widely available as B. schwanefeldii and in many cases is seen on sale more regularly. Unfortunately both are usually offered at a small size (usually around 50 – 75 mm) with little to no information regarding the eventual size of the fish.