Chela cachius (HAMILTON, 1822)

Neon Hatchet Fish

SynonymsTop ↑

Cyprinus cachius Hamilton, 1822; ? Cyprinus atpar Hamilton, 1822; ? Perilampus psilopteromus McClelland, 1839; ? Leuciscus anastoma Swainson, 1839; Perilampus macropodus Jerdon, 1849; Paradanio elegans Day, 1867

Etymology

Chela: from a local vernacular name for the fish.

cachius: from Kachhi a Bengali vernacular name for this species.

Classification

Order: Cypriniformes Family: Cyprinidae

Distribution

Widespread in Pakistan, India, Nepal, Bangladesh and Myanmar although the majority of records are from the Ganges and Brahmaputra river systems in northern India, Nepal, and Bangladesh. Occurrences in Myanmar, in particular, are possibly erroneous.

Type locality is ‘Ganges River about commencement of the Delta’.

Habitat

Something of a habitat generalist, this species has been collected from rivers, streams, ponds, oxbows, canals, ditches, beels, and tanks.

Maximum Standard Length

40 – 50 mm.

Aquarium SizeTop ↑

An active species so even a small group needs an aquarium with minimum base dimensions of 90 ∗ 30 cm.

Maintenance

Choice of décor is not especially critical though it tends to show better colouration in a heavily-planted set-up with a dark substrate.

The addition of some floating plants and driftwood roots or branches to diffuse the light entering the tank also seems to be appreciated and adds a more natural feel.

Filtration does not need to be particularly strong given its natural habitat preferences though it does seem to appreciate a degree of water movement, and the aquarium must have a tightly-fitting cover since this species is an accomplished jumper.

Water Conditions

Temperature: 18 – 24 °C

pH: 6.0 – 8.0

Hardness: 36 – 215 ppm

Diet

Wild fish are likely to feed on aquatic invertebrates and suchlike.

In the aquarium it’s unfussy and will accept just about anything offered. Offer a balanced diet comprising good quality dried products along with small live and frozen foods such as Daphnia, Artemia and bloodworm.

Behaviour and CompatibilityTop ↑

Not an aggressive fish but may intimidate slow-moving or timid tankmates with its constant activity and vigorous feeding behaviour, meaning it’s most appropriate for aquaria containing robust, similarly-sized fishes.

There are plenty of suitable choices including many cyprinids, loaches, cichlids, catfish and characins, although as always when selecting a compatible community of fish proper research is essential.

It’s a schooling species by nature and ideally should be kept in a group of at least 8-10 specimens which will not only make the fish less nervous but result in a more effective, natural looking display.

Reproduction

Unrecorded.

NotesTop ↑

This species is  is unlikely to be confused with any related species given its extremely deep body which fits approximately 3.2-4.6 times in the standard length.

It is currently the only valid member of the genus but it is possible that additional taxa exist, particularly in Myanmar, while a number of former species are currently contained within the related genera Laubuka assemblage, to which C. cachius is closely related. Phylogenetic studies suggest the existence of a monophyletic clade consisting of the genera Devario, Chela, Laubuca, Microdevario and Microrasbora plus the genus Betadevario.

References

1. Hamilton, F., 1822 - Edinburgh & London: i-vii + 1-405
   An account of the fishes found in the river Ganges and its branches.
2. Kottelat, M., 2013 - The Raffles Bulletin of Zoology Supplement 27: 1-663
   The fishes of the inland waters of southeast Asia: a catalogue and core bibiography of the fishes known to occur in freshwaters, mangroves and estuaries.
3. Shrestha, T. K., 2008 - Himalayan Ecosphere, Kathmandu, Nepal: 1-389
   Ichthyology of Nepal. A study of fishes of the Himalayan waters.