There currently exist a dozen described Esomus spp. alhough few are seen in the aquarium trade and none are especially popular. Most are commonplace in their native countries and also quite plainly-patterned so generally overlooked by collectors. Their most common use in some areas is actually as a feeder fish in the aquaculture of larger species. They’re characterised by greatly-enlarged pectoral fins and two pairs of barbels, of which the maxillary pair are extremely long and usually reach the pectoral fins.

Known from the lower Mekong basin in Thailand, Vietnam, and Cambodia, the Chao Phraya watershed in central Thailand, and may occur in smaller river systems between.

Type locality is ‘Thu-dâu-môt, Vietnam’.

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…

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 among the most well-known fishes in the aquarium trade but juveniles are typically being offered for sale with little to no information regarding temperament, eventual size, and potential age in excess of 15 years.

Wild examples are not currently traded, with all of those seen on sale produced on a commercial basis.

This is one of two species sold with the common/trade name of "tinfoil barb", the other being the more widely-recognised B. schwanenfeldii. Despite this it appears that B. altus is just as widely available as B. schwanenfeldii and in many cases is seen on sale more regularly. Unfortunately both are usually offered at a small size (usually around 2 – 3"/5 – 7.5cm) with little to no information regarding the eventual size of the fish. Although B. altus is the …

Juvenile specimens are sometimes available in the aquarium trade although their purchase is strongly discouraged, and this species probably shouldn’t ‚ be considered a home aquarium‚ subject at all given its eventual size plus the fact it can live for‚ several decades.

H. wyckioides can be told apart from mos…

This species is also referred to as ‘royal knifefish’ in the aquarium trade but arguably has no place in the ornamental hobby given its adult size and specialised requirements.

It can be distinguished from congeners by presence of many small, dark spots on the anterior portion of the body which merge to form oblique, irregular stripes extending onto the anal and caudal fins posteriorly.

The ornamental albino variant is widely-available and has become extremely popular in the hobby and there is a commercially-produced anerythristic (lacking red pigment) mutation that has pale yellowish fins and has sometimes been misidentified as E. munense. Also worthy of note is that the specific name is sometimes misspelled ‘frenatus‘.

Most members of Epalzeorhynchos were formerly regarded as Labeo spp. and are thus referred to as such in older literature. According to Rainboth (1996) they’re characterised by absence of a dorsal spine…

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.