Kryptopterus bicirrhis (VALENCIENNES, 1840)

SynonymsTop ↑

Silurus bicirrhis Valenciennes, 1840; Cryptopterus amboinensis Günther, 1864

Etymology

Kryptopterus: from the Greek kryptos, meaning ‘hidden’, and pterýgio, meaning ‘fin’, in reference to the reduced or absent dorsal-fin in members of this genus.

Classification

Order: Siluriformes Family: Siluridae

Distribution

Type locality is given simply as ‘Java, Indonesia’, and this species is currently understood to occur throughout much of Southeast Asia including major river systems in Thailand, Laos, Cambodia, Vietnam and Peninsular Malaysia plus the Greater Sunda Islands of Sumatra, Borneo and Java.

It’s been extensively recorded from the Mekong, Chao Phraya, Batang Hari, Rajang and Kapuas rivers plus numerous smaller drainages across this range.

Habitat

Kottelat and Widjanarti (2005) report that it tends to occur in fast-flowing water and is abundant at the end of the wet season in the Danau Sentarum lakes complex, West Kalimantan (Kalimantan Barat) province, Indonesia (Borneo).

In the Mekong it’s said to be most common in the lowland floodplains but also occurs in some higher altitude habitats in the middle part of the system (Rainboth, 1996).

Maximum Standard Length

120 – 150 mm.

Aquarium SizeTop ↑

An aquarium with base dimensions of 120 ∗ 45 cm or equivalent should be the smallest considered.

Maintenance

Décor is relatively unimportant although this species prefers weakly-lit conditions and may become skittish in the absence of cover.

Do not add introduce it to a biologically immature aquarium as it can be susceptible to swings in water chemistry.

Water Conditions

Temperature: 20 – 28 °C

pH: 6.0 – 7.5

Hardness: 36 – 268 ppm

Diet

Chiefly a predator feeding on crustaceans, invertebrates and smaller fishes in nature, although there should be no need to use such live foods in captivity.

Offer a varied diet comprising sinking dried foods, live and frozen bloodworm, Tubifex, etc., and perhaps the occasional small earthworm.

Behaviour and CompatibilityTop ↑

Generally peaceful though it may predate on smaller fishes and is somewhat timid so does not compete well with much larger, robust or otherwise boisterous species.

Peaceful, comparably-sized cyprinids, loaches and other catfishes perhaps constitute the best options but be sure to research your choices thoroughly prior to purchase.

K. bichirris is gregarious and tends to form schools so ideally four or more specimens should be purchased.

Sexual Dimorphism

Adult males should appear noticeably slimmer than females.

Reproduction

Unrecorded.

NotesTop ↑

This species is uncommon in the aquarium trade although it’s name has been widely misapplied to the congener K. vitreolus in older literature.

These two are easily told apart since K. bichirris does not possess a transparent body in life.

Kryptopterus species are found only in Southeast Asia and the genus has been considered polyphyletic since Bornbusch (1995) with some former species already moved to the genera Phalacronotus and Micronema.

Those still contained within the genus are assigned to a number of putative species groups as follows:

K. bicirrhis group: K. bicirrhis, K. lais, K. palembangensis, K. macrocephalus, K. minor, K. piperatus, K. vitreolus
K. cryptopterus group: K. cryptopterus, K. geminus
K. limpok group: K. limpok, K. mononema, K. dissitus, K. baramensis, K. hesperius
K. schilbeides group: K. schilbeides, K. paraschilbeides

Bombusch (1995) identified the K. bicirrhis group as a distinct clade although he didn’t propose any synapomorphy to diagnose it.

Ng and Kottelat (2013) later noted that members normally have fewer anal-fin rays (46–67 vs. 64–85) than other congeners and placed K. piperatus and K. vitreolus within the group based on this character.

References

1. Bornbusch, A. H., 1995 - Zoological Journal of the Linnean Society 115: 1-46
   Phylogenetic relationships within the Eurasian catfish family Siluridae (Pisces: Siluriformes), with comments on generic validities and biogeography.
2. Ferraris, C. J., Jr., 2007 - Zootaxa 1418: 1-628
   Checklist of catfishes, recent and fossil (Osteichthyes: Siluriformes), and catalogue of siluriform primary types.
3. Kottelat, M. and E. Widjanarti, 2005 - The Raffles Bulletin of Zoology Supplement 13: 139-173
   The fishes of Danau Sentarum National Park and the Kapuas Lakes area, Kalimantan Barat, Indonesia.
4. Ng, H-H. and M. Kottelat, 2013 - Zootaxa 3630: 308-316
   After eighty years of misidentification, a name for the glass catfish (Teleostei: Siluridae).
5. Parenti, L. R. and K. K. P. Lim, 2005 - The Raffles Bulletin of Zoology Supplement 13: 175-208
   Fishes of the Rajang Basin, Sarawak, Malaysia.
6. Rainboth, W. J., 1996 - FAO, Rome: 1-265
   FAO species identification field guide for fishery purposes. Fishes of the Cambodian Mekong.
7. Roberts, T. R., 1993 - Zoologische Verhandelingen (Leiden) No. 285: 1-94
   The freshwater fishes of Java, as observed by Kuhl and van Hasselt in 1820-23.
8. Roberts, T. R., 1989 - Memoirs of the California Academy of Sciences No. 14: i-xii + 1-210
   The freshwater fishes of western Borneo (Kalimantan Barat, Indonesia).
9. Tan, H. H. and H. H. Ng, 2000 - Journal of Natural History 34(2): 267-303
   The catfishes (Teleostei: Siluriformes) of central Sumatra.