P. apogon has formerly been placed within the genera Kryptopterus, Micronema (Rainboth, 1996) and more recently Phalacronotus (Ferraris, 2007) and is an important food fish across much of its native range.

It’s very similar to P. micronema but can be told apart by its longer head (HL fits 4.6± 5.3 times in…

Known from the Malay Peninsula and Singapore plus Greater Sunda Islands of Sumatra, Borneo and Java in Indonesia with populati0ns from Thailand, Cambodia, Laos and Vietnam formerly considered as conspecific now referred to K. geminus (Ng, 2003).

Type locality is given as ‘Bandjarmassing’ which corresponds to a town now more commonly referred to as ‘Banjarmasin’ in South Kalimantan (Kalimantan Selatan) province, Indonesia (Borneo).

Has been recorded in fast-flowing environments but most commonly associated with peat swamp forests and associated blackwater streams.

Many such habitats have suffered degradation of some kind but in unaltered cases the dense canopy of branches above means very little light penetrates the surface of such environments, and riparian vegetation also tends to grow thickly.

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 also referred to as ‘Asian knifefish’ or ‘ghost knifefish’ in the aquarium trade in the aquarium trade but arguably has no place in the ornamental hobby given its adult size and specialised requirements.

It is sometimes confused with the African species Xenomystus nigri but is easily told apart by its larger adult size and presence (vs. absence) of a dorsal fin.

This species is relatively common in the aquarium hobby but contrary to popular belief is not venomous in any way. Its dorsal and opercular spines can pierce the skin, however, meaning extreme caution is necessary when netting it or performing aquarium maintenance.

The genus Allenbatrachus was erected in 1997 to accom…

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 …

Aggressively territorial and incompatible with other fishes in all but the largest public installations and even then may attack its tankmates.

It’s also one of few freshwater fishes that appear unafraid of humans meaning care must be exercised when performing maintenance.

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…